The link to the thread above shows the basics of the F1 fuse replacement but they overcomplicate it. All you need to do is drill a 1" hole at the location 1 1/4" down from ledge, replace the F1 fuse with solder, and your done, and you DON'T have to patch the hole, just leave the hole there, it does nothing. Patching the hole looks like a real pain and is not necessary and all that cutting to make that large window in the side is also a waste of time, just drill a quick 1" hole, plenty of room to work through with soldering iron. The whole job is really a 5-10 minute project.
The '99 will have the newer style white float where the magnets do not usually fall out, but I have seen them leak and fill up with gas, just like the older ones.
Of course, you should test the baffle using a resistance check before removing it. 0 ohms is the reading it should have for full tank, 90 ohm range is empty tank, open circuit usually means the F1 fuse is blown. If it's not reading the correct ohms for the current fuel level in the tank, the baffle will have to come out.
What is the top speed seen on your speedo? The GSXL should hit 70mph on the speedo or real close to it. If your compression is really 120psi, you won't see anything close to that. I suspect your gauge is low, you should try with another gauge if one is available.