You are aware if you start to far off to much, you'll be gear bound and the tach reading is useless, until you get a lot closer.If you have a tach , try a 16 or 17 driver , and a 63 sprocket and see where your at . I would try the 17 first , and also have an 18 , just in case . If you max out rpm's go up on the driver . JMO
That can vary a lot based on the amount of grip the track makes, to stay with normal gear set on rear 53 driver and up the smallest driver you can use would be an 18.What’s a good starting driver and rear gear.