Depends on how often you want to switch and how accurate you need your parts to be. Every time you swap it it will probably get a little less rigid. You would be better off just building two. You can save money by sharing the control board and power supply between them. Or if you are using sheet goods the LowRider is built for that, again you can share the board and PS.
Forget about the idea of changing the machines dimensions every time, it’s way too much work. I think you underestimate the time you will spend doing that. The main issue will be the wiring.
Also, I suggest you to purchase your tubes asap, before printing everything. This way you can make sure that they fit nicely with your printed parts before printing everything. Otherwise, you may end up with slightly too big or slightly too small parts with bearings not making a nice contact on the tubes. I made this mistake myself and regretted it.