By cutting the ends of the bolt plate of a std (non-rail adapter) seat post, you can fit it inside the T7 and bolt it to a KH type seat, but you’ll need to put longer bolts through the seat. It’s only a good thing to do if the height of the rail adapter with the T7 is too much for short legs. Having done this modification, I think it reduces the height about a half inch. more details: New Nimbus 36"
Unless your legs are are too short, you won’t want to pass up on the adjustablity feature of the of the rail adapter and T7 combination.