Hey.. ummm Mailer
I have access to 95 but don't use it often. My bike is an 01 900 SS. Strangley I find I get better economy on ordinary unleaded. I had heard that Euro premium was still only about 93-94 so there was no need to use the 98, at least for the SS. If you choose to use the Optimax, make sure you have an Oxygen Sensor. Mine doesn't so the Optimax is no good for me. The Oxygen sensor reads the gasses in the exhaust to tell the computer whether the mixture is rich or lean so adjustments can be made.
The 98 from BP is marketed as being same as Optimax, I can't confirm whether it is or not. I stand to be corrected but I think the Caltex "Vortex" is 95 and a few Shell Independant sites still have 95. I actually work for an independant Shell site.
Hope this confuses you more haha