Correct, the small MAB's are designed to work with the smaller .068" main jets. Leave the stock parts in the primary side, and installed our .044" secondary metering rods.
Best to call with parts orders, the APT screw is a custom part, we don't have it on the website. I'd also upgrade the carb with one of our rebuild kits. The components are designed for this new fuel, and the kit will come with the correct high flow viton needle/seat assembly, and complete accl pump assembly with new springs.....Cliff