Tire/Rim size for Z1A

Hi All; I want to put as much tire on the ground as possibe. Instead of going beserk, what experience to other riders have? I'm planning on running stock forks and swingarm (beefed up). It looks like a 100/90 is the max for the front. I have a 120/90 on the rear and it looks like I could go wider. There must be some logic/physics to the width ratio front/rear. I will get whatever rims are required/available for these new widths. I'm into canyon carving and prefer function over looks. FWIW, I'm looking at the Dunlop GT501's. The new rims/punching/spokes/lacing is pretty pricey, so I want to get this right the first time. Anybody done this and what were the results/recommendations? Ride safe, Steve