rear sienna seat swivel and l-track?

[meecect]

I finally have found some decent and affordable Sienna seats and they are on the way. What are my mounting options? I'd really like to have both a swivel mount and a track to mount it in, so that I can slide it and easily remove it when necessary.

My vehicle is a 99 Ford e350 cargo van Quigley conversion.

Thanks,
Cliff