Yep, send it back to Corbin they have a option for short people that lowers the bucket raises the back support and positions the rider about an inch forward and I believe down. Not sure if they would be able to use your existing covering though.
Most upholstery shops should be able to lift cover cut out foam to lower and narrow front area which allows your thighs to drop and changes toe tips to soles of your feet.
Otherwise there was a Triumph Factory Solo Low Rider version too. I just bought a New Old Stock one.
LOWRIDER SEAT - RIDER A9701151