I am doing a Speedway disc brake conversion on my dropped stock 40 Ford axle. This kit increases the width by 3/4 inch per side. Can anyone with experience with this tell me what wheel backspacing and or offset seems to work best. I am thinking I want a 4 1/2 inch to 5 inch wide wheel only. I have GM power steering and will run 15 inch wheels and aboaut a 195 X 75 tire. Open to comments for '40 guys. Many thanks.