I don’t use West System epoxy any more ... less their G-Flex 650 product, but only when I want a ‘flexible’ epoxy.
THIN - I buy the $20+ 2-part kit from West Marine, as it is a nice, thin penetrating epoxy - no thinning agent needed!
OTHER - I use the kits from www.raka.com; simple 2:1 mix, no...