Congrats Dave! You got a GREAT deal on the Turner Ren. I have 2 of them, a 4 fretless and a 5 fretless, and I absolutely love them. Regarding the strings, I hated the TI Acousticore strings that came on mine, although some really like them. I believe that is what you have on yours. You might try TI Jazz Flats, the JF365 set fits perfect. I have those on my Ren 5 and they sound and feel great on that bass. I have Status-Graphite tapewounds on the Ren 4 and I'm equally as pleased with those. Let me know if I can help you out with any other info, etc on strings for yours.
Regarding the string height, as long as the neck is good, (never heard of a bad one), then it is just a saddle height adjustment by shaving down the existing saddle. Both of mine have pretty low action. Perhaps the previous owner liked higher action so he installed a taller saddle.
Finally, regarding the fit, etc, if you are going to use it with a strap, you will need to get a "dingus" from Rick Turner's shop in California. It is a wood bar, usually made of rosewood or ebony, that screws to the bass via the existing neck screws and puts the strap button out over the 12th fret. I find the balance is fine then. I also found that I got used to sitting with mine pretty quickly...I actually find it pretty comfortable now. ...but I'm also used to flamenco/classical guitars.
Let me know if you need any other info....and congrats again! Great bass to have in the stable.