on gold tips home page it says 50 ft lb for elk
I shoot the same arrow as you but mine are slightly longer due to a 28" draw
my arrows are 377 grains but I do shoot a little faster at 260 with a 60lb draw weight.
I think you could be like me and try feathers rather than plastic vains
but all in all I think you should be able to bring down an Elk with the set up the way it is now
as to the thunderhead or wasp I dont know I use muzzy's maybe some one else can help you there
but I would not be fooling around with the arrows in case they become unbalanced