I had a quick trawl though some illustrations last night and agree that the majority of the datable illustrations are in the first half of the c15th rather than the latter. However they do occur, but their presence is less generic and they are worn slightly differently.I think an important point to consider is that the wide 'winged' Flemish hood is a variant of this form of Hood. In illustrations of the same date/mss you can see the exaggerated sides of the hood forming the 'wings' more on the better sort than the labourers .... but this is as might be expected.
Similarly I noticed that the later hoods of this type seem to loose their sharp chin/face corner (and hence the wings) in many of the later paintings e.g. Memlinc's Passion Alterpiece where a Mourner wears a red hood (possibly with a lirapipe judging by the fold on the top of the head) but here there is no attempt to follow the fitted shape of a close fitting hood as per the start of the century ( http://www.kfki.hu/~arthp/html/m/memling/altar/index.html )
A problem in looking at these illustrations is the content of the images themselves and the style of the pictures. The datable illutrations of the 1470's tend to be from he Flemish Masters rather than Mss illuminations and there are corresponding differences in content.
However I'll address a few points first before returning to the illustrations.
1. Lirapipe or not
Personally I'd say that in this classic form of the Flemish Hood the lirapipe is almost universal. In the Decammeron illustrations you've shown only 4 is questionable. However 4. does show a what looks like a short lirapipe folded forward. This style of wear appears in some Rene of Anjou illustrations on a slight variant hood and on other headresses into (at least) the 1480s.
Also 4. shows a simplified styling (which may be the artist as much as the hood) and lacks the angle of the 'wings'
2. The 'Wings'
I stand by the fact that if made in precisely the same way as a normal hood with a close fit running from the chest to the throat, round th throat to he chin and then jutting out past the end of the chin, to form what is essentially a tube to surround the face, then when this centre-front seam is not joined you will get the characteristic 'wings'. The 'points' of the 'wings' being the chin-face angle.
Certainly as the hood became less functional as a closed hood I'd expect this to become exaggerated over time, particularly amongst the more middling sort rather than the labourering sort. In the same way that the (to use the French name for convenience) Chaperon developed from a real hood.
The neck sectoin appears to become smaller. the angle more exaggerated, but the form is still essentilly the same.
3. Prominence of the hoods 'wings'
It is just a though but for a garment of this sort a little starch might work wonders ... notice in the JPeg I referened before that the Lady's 'wings' are far more rigid than the cllapsed form of her maid.
Ok now to the meat ... hopefully this will make sense (like any of the rest has!)
In Jean Le Tavernier's c.1460 illustration of a Burgundin Marketplace a seamstress is steated in the bottom left of the picture by the gate. She has what is almost certainly a Flemish hood.
In a mid c15th copy of Froissart showing the Jousts of St Ingelvert (British Library MS Hrley 4379 ff19 & 20) in the background women ae visible wearing Flemish hoods.
In a Mss in the Musee Conde in Chantilly called Le Rustican, and dated .1460, the months are depictd by various labours. December shows a Woman wearing a black Flemish hood with the lirapipe wrapped around the head. It's worth noting that in the summer months she wears only her kerchief.
A mourner in the Entombment by The Master of the Virgo Inter Virgines (last 1/4 c15th prob 1490) has a white kerchief visible below a black Flemish hood.
In a mss of the Roman de la Rose which is frequently used but I forgot the Mss (sorry) but from the clothing dates to c.1490 I'd guess a Woman is shown seated with a distaff, on her head an be seen the edge of a white linen cap covered by a red Flemish hood.
In an illustration of The Hours of the Virgin c.1500 women in the fields are shown wearing Flemish hoods, one red, the other Black (with the lirapipe wrapped around her head).
Again there are the c.1470's Ferreting tapestries (incl. one in Burel collection in Glasgow) which show women wearing the Flemish hood with the lirapipe wound around the head.
There are certainly variations to this hood both by date and locale, identifying these subleties is more difficult. But a clear derivative is visible in the illustration of 'The City of God' of mid c15th date in the Bibliotheque Nationale in Paris (ms fr18 f.3v) which shows plainer versoins of this hood, the sides are flatter and more rectangluar, more akin to he frontlet in shape, but clearly of a lirapipe hood.
In Rene of Anjo's Book of the Tournament the scene depicting the Review of the Helms shows a maid carrying her Lady's gown wearing what appears to be a small frontlet-style hood with a lirapipe folded up on top of the head (this must require pinning?) but the chracteristic 'u' loop een on frontlets and henin-style headwear ... this is probably a pin.
In the Beuachamp chronicles this develops further where the hood has become a frontlet and the skull is covered by a small square cap.
So in summary. I still feel that the Flemish hood was widely worn in an informal manner by most middling and lower degree women, but it was ceasing to be the standard fashion accessory of the 1430-1450's. The fitting became less precise and the wings developed into the frontlet as the fitting became more subdued and rectangular.
As a BTW one of the Badges worn by the noblemen listed in the 1475 Expedition of Edward IV to France is described as a 'Flemish Wives Hood' (or some close appromimation to those words)
OK ... any comments
Cheers
Dave