This is what I would do first. If you think about it when you are cruising most of the time you are running of the transfer slot circuit which can be leaned out by the idle feed restriction. I know most of my part throttle cruising I am running on the tranfer (transistion) slots so if its fat at part throttle cruise I would lean out the (IFR) idle feed restrictions. If you are happy with the rest of the carbs settings then leaning the idle feed restrictions wont effect the other circuits but you may just have to adjust your mixture screws when done. I believe most billet metering blocks should have jets for the IFR. In the older carbs we would put a small piece of wire in the IFR which also would lean it out some. But I believe yours should have jets in them already. They (the IFR) can also be drilled and have jets installed in them as "Hemmings Muscle Machines" mag had an article about doing that a few months back. Ron