Presuming "spraybar" means inlet to the carb. I think I will try the 55AX inverted (or at 225 Deg when seen from infront) as recommended by the manual. Just to cutout other variables, I will use my old 55AX rather than a new one. For the Topstar though, I am thinking I will try out someone's 91FS on trial basis before I buy one for myself

Will keep posted about the results.

Regards
Ameyam