I'm looking for an extra base to use with my Soundseat Retrofit. The Gibraltar 9608 is plenty sturdy and it has the right diameter post but I sit pretty low so I'm concerned about the height. It's a little confusing because when you look up just the base it says it adjusts from 20" to 28". If you look up one of the thrones that uses the 9608 base it also says it adjusts from 20" to 28". If the 20" minimum includes the seat then that would be fine for me but if that's the minimum height of just the base then that would be too tall. I was hoping someone here owned one so they could verify the height for me.