Hi Scott
As has been stated already, you can count up to 30 hours of Vigilant PIC time towards the CPL licence issue. However, ISTR a little footnote in LASORS that says you can't count it towards the 100 hours PIC requirement, so it may or may not end up being useful (depending on how many dual hours you already have...)
As far as the TMG rating goes, I believe you can use Vigilant hours towards satisfying the training requirement, but you will have to fly with a TMG examiner in order to gain the rating (i.e. you will not get it directly through the VGS system). Everything you need to know is in LASORS (just make sure you read it all carefully!!
Finally, I can't recommend the VGS system enough. A great way to gain experience doing something different, and will improve your flying no end (not least your capacity and general handling skills!). Hope that helps.
LAI (VGS instructor and current IR student)
P.S. Genghis. I always thought I'd enjoy chatting with you over a pint...now I know!! Did you have a hand in the very interesting spin testing writeup in the ACM by any chance?