What would you do with her mane?

Your pony is so lucky to have a long thick mane, I would leave it too. Ziggy is very folically challenged and has hardly any mane really, but even so it won't stay on one side!
 
See even though it's a double mane it still looks neat and tidy Whisks' is just bonkers, like it has it's own ideas on how hair should grow defying the laws of gravity.

Only looks tidy because I brushed it with a parting. Usually the wind plays around with it.
 
newrider.com