This thread reminds me of the old joke about the tourist driving around Ireland. He gets lost and stops to ask the way...
" Ah to be sure, If I were you I wouldn't start from here..."
But back to one of the questions, I wouldn't try making traditional ELB horn nocks out of any wood, I'd think the risk of splitting is far too high. Even horn has grain but it's much more homogenous than any wood.
Waterbuffalo horn is pretty cheap and easy to get hold off (well it is in the UK), failing that, an Ebony tip overlay would look really cool.
I did a V narrow light weight Ash ELB for someone at the club who is just starting out, I didn't want to put in too much work so I did WB horn tip overlays, I heat treated the belly to keep the weight up and set down as it had ended up V narrow and underweight due to finding a crack in the stave late on in the process. It looked nice in the end and I named it the Needle
Bow making is great for teaching patience and humility... I was always a cocky impatient young git.
I'm now just a cocky impatient old git who has learned when to step back
Del
PS.
There is a good pdf download on making Ash ELBs from Alan Blackhams backstreet bowyer site. Some of it will be stuff you know, but there is some great stuff about
exactly the sort of bow you are trying to make.