what type R value insulation for 960 sq.ft. garage
Code minimum is generally R-13 for insulation inside stud walls, or R-10 for  insulation outboard of masonry walls. More is always better. But this question is far too broad and subjective to be satisfactorily answered; it's like "how should I build a house?" You can insulate your new garage any way you want, limited by the building code and existing construction (Frame? Block? Something else?), and subject to correct installation for the method you choose.