I've used wiring from 3 different suppliers - all were fine, and the correct factory configuration, for either generator or alternator -
you'll find folks to recommend every make, so you're best to just use a dealer you like and trust! remember Jim Carter [your area] has a 20% off sale right now
"extra circuits" just means a few more spots on the fuse panel, and the original fuse panel [not always installed, but available from most repro places] has about 3 'ACC' fuse spots that should do ya, don't need to order the very expensive packages some sell for all the street rod bling that you'll not likely use
Bill