I need help w/ the rules for hunt seat for kids

Ok, so I’m use to riding saddleseat, and was always taught to ride and show saddleseat, so I don’t know all the rules for hunt seat.

My step-daughter will be showing hunt seat lead-line this year and I want to make sure I know the rules for that. I sometimes see kids wearing tall boots, and sometimes see them with the strap thingys around the top of their calf. What do I do for a 6 year old? Or is it dependant upon experience? Or preference?

Do we have to match exactly w/ leadline? Or can her coat and shirt be a different color than mine?

Anything else I should know?