I have not had GC in my car for a long time, but I have a lot of it. I got sidetracked last year and a half with ARX and alternating between ester/ARX and non-ester oils to treat my seals. Now I have run T&S, twice in a row, because I felt it'd do a good job cleaning and clearing my engine plus conditioning (softening) seals. NOW I AM READY to go back to my 7+ cases of GC starting this winter. No more 6mo/11k intervals, I will do more like 4mo/8k. Anyway, my question is should I do a run of conventional to clean out that dirty T&S (it IS dirty, @ 9k miles) and set my seals? Better than going right to GC, correct? I'm pretty much planing on it, but am looking for peer support and last-minute advice. I have a bunch of 10w-40 Chevron Supreme and Havoline Synth 5w-30 designated for it already. 2 months enough for seal-set? TIA.