A good point by CA and others on series-parallel. With 4 panels on 150V controller this is inevitable, and this complicates the install.
Though I have some doubts as to 4*250W on class C roof. You want to keep at least 14-16" from A/C, and some smaller distance from vents, and to be able to get around those panels for cleaning, fixing - and for installing them, to begin with.
Old suggestion that comes here often - make a cardboard template of panel and go up on the roof and see.
Flat 750W at sea level will likely not exceed 45A. If price difference is important, get 45A with this. If it isn't, get 60A.
