This was an intresting discussion.
I use the G25 with the H-shifter and have the clutch_Threshold =0 but still I brake with my right foot, because I don't think it is ok not to use the coast lock of the differential which you don't if you have ANY gas on while braking (see Niels Heusinkvelds setup guide 0.91). Yes, the car is more stable under braking if you brake with your left foot and use a little gas, but where is the fun in that
Isn't GPL all about it being difficult? OK, so I ought to have the clutch_Threshold = 90, but hey, who's perfect, maybe sometime.
So, do I go quicker with the G25, H-shifter? Yes I do, but I didn't at first when I got the G25, some 6 month ago, I was much slower and had all the problems you have mentioned in this thread but now I can't even think about using the paddles, instead I use the paddles to look around.
When downshifting i often go 5-4-3-2-1, (I don't like the 6-gear cars), often using the clutch even though I don't have to, during braking but it happens that I just go from say 5-2 so that I can concentrate on braking with my hands on the wheel. If I do that I of cause have to use the clutch.
And I use Birkenstock sandals on my feet, and I love the "Spell Check" on this forum