It's a shame that you haven't quite clicked with the TT SuperBikes game.

Combined with Silja's amazing course knowledge thread, it helped to give me a very full understanding of the track.

I understand what you mean about the bikes handling in the game, though.
I wonder what view you have been using.
Behind the bike, for me, seems very unnatural.
The view through the screen seems to give me more of a sense of control.
(Use the joystick, not the buttons, for steering.)

If onboards are working for you, you could try Marc Flynn's lap on a 600 from the mid 90's.
105-110mph-ish. But obviously the track has changed a lot since then.