The main toroid is a 250VA 25Vx2 transformer. 250VA rates both secondary windings together.basically take the VA rating and divide that by the input voltage to get close to your max mains current draw, then increase that by perhaps 30%-50%.
250/120 =
2.1 + (0.4 * 2.1) =
~3A
The other transformer is a 12V 1A (6-0-6) transformer, which makes the VA around 12VA.
12/120 =
0.1 + (0.4 * 0.1) =
~0.14A
Okay so perhaps I was a little off on my calculations.
I think a 3.2A slow blow would do the trick. I'll never be drawing that much under any reasonable load anyway because the speakers that it will be hooked up to will be blown out by then.