Hi Guy,
Sorry for the delayed reply!
Your Quark looks fantastic! Looks like the V4 no?
For the CofG, correct, 79mm from LE is what everybody agree on. You can go either way from that point 10mm back or forward without too much problems.
Anyway, Quark is really looking good! Wish you all the best for the first flight, and hopefully, a lot of fun!

Keep us posted of course

Fred