I would love to try 12x20 but, alas, I can't carry that much weight/bulk anymore. I've just recently finished assembling a lightweight 4x5 kit dedicated to 6x12cm RF and will soon be looking for a nice used Canham 8x10 Traditional for sheet film. Even the 8x10 will often be a challenge for me. This is why I also have the 6x12cm kit.
The LESSON to be learned is... if you want to do something then do it NOW. Time slips by rather quickly. You never know when your age and/or your health will take a turn... and it just might happen sooner than you expect.