Douglas B-66 Destroyer

I was watching the movie BAT 21 with a friend earlier tonight, and I got curious about the B-66. It seems most of them were recon and/or electronic warfare birds, but 62 actual bomber versions were built designated B-66B. I’m wondering what weapons and stores the bomber version was cleared for. How much could they put in the weapons bay. I know they had a hardpoint under each wing for a 500-gallon fuel tank, but all weapons were carried internally. Anyone have info on what the Destroyer carried for an offensive punch? Also does anyone have any idea how many rounds were provided for the tail-mounted 20-mm guns?

Oh, and was this aircraft also nicknamed the Whale, like it’s Navy A-3 brother or was that only a Navy thing?