Widest rim and tire for full mini tub to frame

I just want to make use of all available space if I am going to the trouble of moving the springs in and full mini tub should be the term for what I am doing,ill be using trailer fenders and inner walls for the mini tub so I can still use the back seat and thanks for all the help I appreciate it,i got the trailer fender idea from another member on here there is a thread on it somewhere,i was hoping for 325/50 tires on 12" rims but if I can get 335s by trimming the wheel lip that would be great.ive got my 8 3/4 all set up to narrow so I'll have to get the inner and outer original wheel wells out and trim the lips and get some tires mounted and see what will work and how much I can cut rear and still be ok.