Can't recall, maybe Mike C tried higher values for R1 and R2 - he said what those were, can't recall - hgiher than my 10X though and pretty sure proven to work fine. I used 10X factor because I had them, common sizes. But I also bought limited qty of values bout 3X higher than that, effective cutting the R1/R2 drain by another factor of 3 -- didn't try this yet. Dunno if there is a theoretical limit on the values, but 1M or 2M for R1 sounds familiar think it was tried and worked.
The 13A is well proven to tolerate spikes better than the 25/45/85, so, these gate resistors are probably not needed at all on a 13A, but on the scope, things look much better with them.
More important for reducing parasitic drain than tweaking higher R1/R2 is making a correction in the firmware to shut down the AtoD when goin in sleep mode - forgot the difference but it's big. First recommended by Halo in the 24/45/85 thread - dunno, others might have done this in custom firmware but as far as I know, none of the standard open source versions do it.
I'm seeing 0.007 - 0.009 mA drain in a few stock better lights, so it's done and out there. For me, I just think no one should have a concern about draining the battery simply because it's left in an e-switch flashlight vs. a power switch light.