My saddle on my trainer is just uncomfortable. I had an older Specialized Phenom then switched it to the stock saddle off my new trek.
So I’m going to try a new saddle, a FIZIK Tempo Argo. I know you often can’t return or get a refund if the rails are marked up. Is there a way to protect the rails while you are testing the saddle?
Try cutting up an old tube and using a piece of rubber to protect the rails.
Electrical tape wrapped around the rails may work. Thin enough and the adhesive can be removed with relative easy if it transfers to the rails.
Good idea.
Cling film wrapped a few times worked for me, compresses well but is still strong enough to stop marking
I have some silicone tape for my to finish off my bar tape. wonder if that would work…
Probably work just fine for that.
Most shops have specific trial saddles available. Maybe see if the retailer you’re buying from has this option to avoid any worry.
I’ve asked… most of the shops I’ve been to don’t. One does but you have to rent. That’s fine, but it’s really just to get you to commit money so you buy from them because the balance could be applied to certain saddles.
Ah, yes. One of my LBS did this a few years ago.
Couple of wraps of PTFE tape on the rails has worked for my last few
I’m finally taking this advice! 
Tired of using a heated spoke to brand the electrical tape I used to finish bar tape only to find it flapping in the wind a couple hundred miles later. Got some X-treme tape & I’m going to give it a try.
Had to hope in the way-back machine to find this post that originally gave me the idea.
It’s worked for me so far on the trainer when I changed out my super old bar tape.
I’ve used electrical tape for this purpose. Don’t overtighten the clamp and don’t do more than a couple of trainer rides. It’s worked every time.
@RydeRuff12 how did you like the fizik tempo argo saddle. I am considering it now. Currently on a fizik antares and it has been good but starting to think I could have a better fitting saddle. Was going to try the 150mm. I think my Antares is a 145mm?
Any feedback would be great.