Well then you know the drill. IMO, outside of swaping in stiffer springs there isn't a whole lot else you can do for a reasonable price that will have a lot of effect. 10 weight oil seems like about the right grade to me for this bike. 15 weight might give you too hard a compression stroke and something lighter (8 or 5) would make the rebound too quick. You could mix 10 and 15 and get something around 12ish.
If I were going to experiment I might try raising the level of oil a little. It seems 166mm is low compared to the Thruxton(143) and standard Bonneville(120) but this maybe due to the amount of rake in the forks.
Keith
