I could accentuate the forearm veins a bit more , just realized that they're not so prominent like on the concept art. I'll see what I can do about the bicep vein. Gotta research a bit more based on what you said :)
biceps could be a bit thicker, can shorten the abdomen and tighten the belly area a bit, he's actually not very fat, despite first appearances. Pecs could be a bit smaller. Legs can be thickened too, with less definition of the calf muscles, but just strengthened all throughout. The head can be a little smaller. You can…