8.5" wide? Very, very nice! As for the tyre size, tough choice. It'd be cool to have fatter ones on the rear, but then you need to replace those separately... They will look tops on your fine beast, anyway!!
Yeah rotating them is a thought, but really have you HONESTLY ever done it, I would guess no, and replacing two worn front tyres cause of alignment issues (potholes or whatever) is cheaper than 4 cause you rotated them and now they are all worn.