With all things being equal what would be the best limb core wood for a Hill style bow?
Bamboo.
From what I have read and experienced it's more of a personal choice rather than a performance choice. An all wood bow is another critter of course. Some will say lighter cores like Bamboo increase performance, that is why Hill chose Bamboo. But, John Shultz liked Yew as well. I do know from asking silly questions that foam is not really an option. Got that from 2 different bowyers, nor is carbon backing any significant enhancement. My conclusion (in my mind anyway) is it's the bows design more than the materials than make a difference
Allen Boice of Liberty longbows said he liked Yew and that there wasn't a thing wrong with bamboo IF you use the good stuff.
I have no idea what makes a wood the "good stuff".
I have or have had, Osage, walnut, yew, bamboo and yew together. All have worked well but bamboo is the lightest in the hand and I prefer that .
I have a Dave Johnson cedar longbow and it seems to shoot as well as my two HH bamboo longbows best I can tell. they are all different draw weight bows though so it would be hard for me to do a real side by side comparison but the cedar core bow seems to shoot good.
Bamboo the good stuff.Some bamboo can be springier than others.Some temper it with heat as well.Talking real bamboo like Moso or Tonkin.Not actionboo.
I have had the pleasure of talking with some very talented bowyers over the decades. Bamboo, is very popular among the longbows, but not all bamboo is created equal and the best bowyers have specific bamboo they use. Yew has been popular with a lot of bowyers, but many do not like messing with it, do to health reasons. I have been told by a few great bowyers that maple is a great core wood and I can say from experiencing it, that to me couldn't tell a difference. In the end, it is the core wood you like, as majority of the performance is from the fiberglass.
I have bamboo and yew. Both are extremely nice. All 5 of my HHA bows are bamboo, and one of my Northern Mist bows is yew. In my opinion, the bamboo feels a bit springier, and the yew feels smoother. Some of my friends don't seem to notice a difference.
I shot red elm cores for year than I order one with bamboo and I really like I had a Liberty Classic with yew core very smooth but I like the snap it bamboo I feel like I get off the string cleaner. I have a Yellowstone Longbow with tempered bamboo I like it a lot.