Personally, if I only wanted a single BTS bottle and were going minimal I'd just use zip ties.

I will say that while I usually race with a single BTS bottle I do find it really helpful to have a second bottle when training, especially now. I recently got this Topeak mount and I love it. It's incredibly easy it is to switch between a 1 bottle and 2 bottle BTS setup (previously I'd have to swap between two different setups that were single bottle only or two bottle only). It also tucks right up close to the saddle and angle adjustment is really easy. I don't use the CO2/inflator holder so I just took that off.

I stumbled on the Topeak after first trying the Profile Design RMP, which is a more minimalist version of the same idea but it didn't fit with my saddle (ISM Attack). The TriRig Beta is also similar, but doesn't let you adjust the bottle angle. So I gave Topeak a shot and it works great.

As a side note – I still have the Profile Design RMP sitting around. I'd be happy to sell it at a good discount if you're interested.

Agree with Northy, the Supacaz has only 1 cage at 1 angle. I've been using various setup over the years with 1 cage mostly to carry items for long distance rides not necessarily hydration. But all the ones I've used I've always have had the ability to switch between 1 or 2 cages. I wanted something that was lightweight but not flimsy, looked decent and had multi-use capability. I hadn't seen the Topeak which looks nice probably because I've been happy with what I have.

I have the http://www.valdoracycles.com/...saddle-bottle-holder on 1 bike and the TAXC on another.

I'd suggest you use google search using the images entering behind the saddle bottle holder to see all the variety of choices before dropping $20 on the Supacaz. I think you can do better.