Looks nice Mark.
You perhaps could have gone another 10 or 11 exposures... As far as the star colours go, your best bet with a DSLR is to take a few subs of a shorter exposure duration (something like 10x60sec) to record the star colours, then stack those up, stretch it slightly to bring up most of the stars, and then select the stars from the shorter exposure, and layer them into the longer exposure image.. You can then adjust the opacity a little to suit, and maybe even boost up the saturation to give you very vivid star colours..
Funny you should image M6... I was planning to do either M6 or M7 this weekend... Now I'll go M7..
Cheers mate..