I have never run my GLR on the rough side but I have run plenty on the rough side with my MR03's. I bet you could get away with KS Softs on the rear of the GLR. I will run either Softs or Super Softs on both my 3500kv GLR or my 48t LM MR03, I find that the SS's give a wee bit more forward bite but the Softs, especially if the temp is 69* or more, work just fine. I do not feel any difference in lateral stick between the two.
On the front I normally run Mediums but being that you are running the rough side you may very well be able to get away with the firms.
I was a long hold out switching over to the smooth side. When I first did it I hated it, I had to re-tune all my cars, I was traction rolling everywhere, the cars felt weird, and I just did not like it. Now that I have been running on the smooth side for 6 months and have some rubber on the track there is no way I would ever go back. The smooth side offers more consistency, tires last a lot longer, and it is so much cleaner. The cleanliness was a big thing for me. There was so much junk coming off the track that I got filthy running my cars. Running on the smooth side there is still some tire/tack dust coming off the track but it is 1:10th what it was on the rough side.
Cheers,
Jim
Great info there! Found some KS medium and firm fronts and have them on the way. Also grabbed some KS-M softs for the rear. I’m willing to try anything at this point. 😂 Will be running the smooth side after things get back to normal around here. We definitely make some tire dust!