Quadruple-Digit Post Count
Awsome! One more reason to go for KB Muscle. 20s will be perfect, if not too light. You might even consider 22s (20s plus a 2kg magnet) or 24s. The book said you should use a pair of bells that you can comfortably double press 10x (but not a 10rm), I'd say use anything that falls between your 12-15rm and go with that.