I have not met this reed so I cannot vouch for the accuracy of the information presented below. However I have already made 1 reed from the Quinn diagram which seems to play very well in both the Quinn "O'Flynn Copy" chanter and in the Quinn-copy "Penny-Chanter."
I have worked on Liam's pipes many times and I have cleaned the Rowesome reed at lest four or five times. Quinn's staple copy is correct however the reed length should be 3 3/8" and the width of the head is 19/32". The distance between the binding and the reed tip is just a hair over 7/8" however liam has pushed the bridle up and wrapped string under it to hold the bridle in place....this distance is 23/32" from the bridle to the reed tip.
This is a "hog" of a reed. It is the largest and ugliest reed that is playing in any chanter that I have seen. It is also the best sounding and easiest to play. The reed in Paudric Macmathuna's chanter is almost identical, as it should be because Paudraic's chanter is identical to Liam's.. so much so that Liam's reed will play perfectly in Paudric's chanter. Paddy Keenan's reeds are very close to the big Rowsome's but he uses the strange bridle placement.
You may post this if you wish. Also Rowsome clipped the corners of the reed at an angle like this /----\
Click Here to view the 75 KB line-art .gif file.