The original bow was thought to be close to #100. That would justify the length. For example, I just made an English longbow for a customer that wanted 60#@26". I made it 66" long and it shoots quite fast with no hand shock. had i made it longer I would have been compromising that performance. Dylanholderman has a good point, I think you could follow that advice to a degree, as long as you are going for a higher draw weight and longer draw length. The thicker, bigger tips don't help in this regard. There is a little more mass in the outer limbs than your average bow which wouldn't really be a problem on a warbow but when you lighten the draw weight you really start to feel those tips come home unless the the bow is proportionally shorter. The first one I made was 72" long and 50#@30". It was slow and shocky. I remade it at 68" and it was soo much better.
