Any race or roll on with a Harley is just foolishness for them. Ask them to set the rules for the event because it doesn’t matter. They have a six speed so just specify wether it’s a top gear only or any gear. At 60 mph you’ll win in any gear you choose. Fourth will give a better jolt and spank them harder. Third will make high rpm but I don’t know how your limiter is set but very doable. It’s really about how bad do you want to make them look.
My limiter is set at 7250 rpm and with the mods I have in my 2014 Roadster I’d go to Second for max intimidation factor. I top out second at 90 mph, go to third for a buck twenty and then fourth and fifth is just to bring the rpms down from scream.

It’s going to be hard not to look to arrogant and smug.
I’m still waiting for a Harley rider to try me out.