*sigh* This is going to be interesting. For me in the F-Type, my Mediums at the beginning with full fuel load start falling off a cliff at the end of the 6th lap, and my Softs with low fuel load start falling off a cliff at the end of the 6th lap as well. The Hards start getting slower than very worn Mediums and Softs after the 7th lap on a low fuel load. Luckily I can fuel save enough to stretch the fuel to 14 laps so I can play around with tire combinations if needed, but I'm not sure which minimizes time loss.
I'm thinking of 6M/7S/7H, unless I start from the back, where I'm thinking of maybe 6H/7M/7S, although I won't be able to test this out due to time. I'm thinking the lower fuel load will let me eek out another lap on the Mediums if I don't start on them.
I'm able to get 14.5 laps or so out of the F-Type by shifting at 50%-60% (where the Gear Shift number ends), if that can help you with fuel saving at all. I don't believe I'm losing too much time doing this.