I have 205/75R15 radials on 4" or 5" rim, I need to look to be sure what size they are, aired up to 32 psi on my '37. The rears are 235/75R15 on a 7" rim. Mine drives very easy with a 1941 steering gear box ( same as your '42-'46 ) gear box. I've had this size tire combination for 26 years with no issues. I have a 250 inline six / T350 automatic with straight axle, so its lighter weight than a stock 215 would be and lighter than your 350 and 700R4. A 205 might be a little lite for your weight, so look at each tire size carefully.
