Seen several topics guessing about this on offical forums. No authoritative answers though...
What would I need to feasibly start doing ToCr10 ? T8? T8.5? T7.5?
Seeing as ToCr is the next tier after Ulduar, it's most likely to require wow gold gear. Like Ulduar 10 gear for ToCr 10, and Ulduar 25 gear for ToCr 25.
Gear progression in wotlk:
naxx 10>uld 10> toc 10
naxx 25> uld 25> toc 25
If you go:
Naxx 25> uld10, the 10 man content will be a lot easier.
If you go:
Naxx 25> Uld 25> toc 10
Toc 10 content isn't going to be that tough.
I pugged the first two rounds of ToC without much difficulty.
I would use a site like www.wow-heroes.com if most people have a 2300-2400 gear score I believe toc 10 (prior to faction champs) would be pretty easy. Depending on what faction champs you get they might be easy as well.
http://www.mywedding.com/lichking/blog_post_90621.html
Were you in a lot of the BiS Naxx gear? Remember that the stuff that dropped off of 25 Maly, KT, and Sarth+2 was actually the same ilvl as 25 Ulduar.
The first 2 bosses in ToC are severely undertuned. I've certainly seen groups fail on them, but it's either been due to pure bad playing (people standing in fire) or severely undergeared tanks.
Normal ToCr is very very easy. We have two new wow gold geared in badge gear (2 * T8 etc) and some drops from ToC 5 man and they could easily join in on the ToCr normal runs.