elderly.com is a great outfit to work with. They will also set up your uke to how you want it, make sure there are no fret buzzes, and check the intonation and the integrity of the uke. Ask them about it to make sure you get the set-up you want.
I've been dealing with Elderly since the 1970's, before the internet was born and they were a simple mail-order business... I've bought and traded and sold many instruments through the mail and they have always been excellent and honest folks to deal with!
The difference between a tenor and a super tenor is the scale. A tenor uke has a tenor size body with a tenor scale - about 17". A super tenor has a tenor body but has a baritone scale - usually somewhere between 19 and 21". Some super tenors are tuned GCEA, gCEA, DGBE, or dGBE. If you're getting a super tenor, ask for what the scale length is and how it's tuned and what strings does it use for that tuning.
Have fun!!!