Effectiveness of oxybutynin gel for palmar/plantar hyperhidrosis?

I came across an 8% oxybutynin gel product and it seems relatively newer, so there isn't much out there, but reviews look positive and my PCP thinks it could be great to try. I sweat primarily from my hands and feet, but historically no treatments have worked in these areas. Anyone one have experience with this oxybutynin gel product before?
It's from a site called Twofold