Thanks for the video man! The turn-on rpm / idle output is a very important thing. You are right that bigger are not automaticly better.
I have also "only" a 180A/200A HO Singer (stock 90A) with stock pulley. Since there is no speed limit here, its good to can drive with >155mph and dont need to worry about the alternator.
Optima is good choice, have it too.
Best regards from Munich
Bari