I think hand shock is one of those grey areas, what one perceives as hand shock, another may think is fine.
I suspect that one cause is simply poor grip comfort.
ELBs (especially laminates) of tend have rather flat backs with a noticeable corner where sides meet the back, that can really bang into the knuckles.
Similarly if the belly is too flat and the grip poorly shaped it can bruise the lower thumb joint.
I've noticed this on some fairly wide warbows and a bit of fiddling and fettling round the grip sorts it. I have an 80# hickory backed Yew and I added a leather pad on the back, blended in to give a rounder grip which made a huge difference. (It looks odd without a leather grip covering the whole grip area... but I can't be bothered!
as I rarely shoot it... it's my only 32" draw bow, so it's just for demo' )
Personally I don't believe arc of a circle tiller is to blame as such, maybe it's more like excessive bend in the centre.
Some longbow "designs" are roughed out even thickness and with over the centre section (maybe 20"), which to me is wrong. My thickness taper starts pretty much from the centre (or a couple of inches either side), and I do fade up a whisker to the grip, so you automatically get a slight thicker grip.
I think there are other contributory factors like brace height too low (or too high?
) Arrow not well matched to the bow etc.
Maybe it's a lot of little details like much of bow making. Once a bow is shootable there is still plenty of tuning to be done.
Maybe just lightening the tips won't help, but if a few other things are done as well, hopefully the problem will get resolved.
Del