Switch testers are quite nice even if they don't have the exact switch you want. It's a lot easier to figure out what the numbers and descriptions mean if you have a comparison point. The switches I ended up with were not in any tester, but the testers were still super helpful.
As for layout, it's worth being open to the smaller things like CRKBD or Lily58, your brain is better at adapting than you may think. These layouts save desk space, are significantly cheaper, and are quite nice to use. The savings add up especially quick if you are trying out different kinds of keys.
Or "let's finish setting up your PC" full screen on a 4 year old system. Then you click through just to find the only options are 1) share more data with Microsoft, or 2) make Edge your default browser. The day I find a decent note taking tablet running Linux, windows is dead to me.