wheels for 88 mcss

alright people...all suggestions would be very helpful!! i currently have stock size rims...which make my tires go flat...i have 275/60/15s out back, and 225/70/15s on front. i was thinking of getting 15x8 rims for back, and stay with 15x7 in front. the backspacing would both be 3.75"...would that be alright, or would it rub? im not too sure about this... would 15x10 in back fit with 275??
would 225s fit on 15x8s??

also, the 15x10 have 4" b.s. that would rub? i havent checked to see how close the tire was as is...