212 Man,
Fascinating post. During OEI training we only allow 64.9% Tq/ 97% N2/Nr, and would only allow the RRPM to go as low as 91% during autorotation. You say you go that low after "engine failure"; do you really mean OEI or double-donk-stop? I've certainly seen nothing that permits power-on below 97% in the Bell books.
My understanding of Bell's limits is that they are either "normal" op-applicable or "emergency". Topping isn't usually an emergency, at least not with our engineers! Your other topping points all appear valid to my limited brain, but surely they'd be better covered during ground topping?