Before you start cutting, I suggest giving the Corbin a little while to settle. I got a Corbin last winter have used it for about 1,000 miles so far. I'm liking it and am playing around with the seat height and riding position to get it optimized. Here's my short seat saga:
1) Didn't like the basic seat due to the tilt and softness of the foam. Preferred the high position over the low. Road this way for ~3,000 miles.
2) Did the seat mod to reduce the tilt. Much better, but the foam issue remained. Road this way for ~3,000 miles.
3) Got the Corbin and found that with the high position the tilt was much less of an issue. Generally OK. Still breaking it in.
4) Picked up a '87 BMW K75S as a project bike. This has a much tighter riding position than the S10. Looked into the Master Yoda Riding Position.
5) Rode the K75 one morning then hopped on the S10 in the afternoon. Was shocked at how different the riding position felt. The S10 was wide open, my thighs were pitched more down and I found it more awkward to grip and lever with my knees. Trickier to do the Master Yoda Riding Position, or at least of less apparent value in terms of control.
6) Put the Corbin into the low position. Much better posture and ability to "bend at the hips, not the waist." No tilt issue at all. The lower position put my knees into a better position for grip and control.
I'd still prefer the high position in terms of my Achilles tendons (the tense up a bit) and reaching the ground, but I'm starting to get used to it and like the low position on balance. It makes the MYRP easier to exercise, which has helped with control and how my back feels after a ride.
I only offer this as a suggestion on using the Corbin. You will find the tilt is not as extreme as the stock seat. But I suggest playing around a bit with your riding position (check out Master Yoda) and with a low seat setting before cutting things up. The high position was my favored one until now and I'm questioning my bar risers and their positioning. I have a sense that some of the tilt issue may be due to how folks choose to position themselves on the bike. I may experiment a bit with the old seat and the MYRP to see if my hypothesis works.
Whatever you end up doing, I'm sure you'll like the Corbin. Much better than stock.
Eville Rich
2016 S10
2015 WR250R
1987 K75S