Well one thing I would suggest to start is get the 198 header if your running the C6 in a truggy. As for the needles, when I was there a month ago both my LSN and HSN were very close to flush. I never use a temp gun so I can't really say what my temps were down there but I generally just make sure I can touch my hand to the head for a second.

Also your temps are going to be a little hotter untill it is fully broken in. Once the motor completely frees up your temps should drop a good 20 degrees. Next time you temp your motor and the temp gun says 265ish try the spit test right away as well, if it really is 265 the spit should burn off very very fast. As long as you have good smoke and you don't have any lean bogs from the engine I would say you are fine.