I hope your bubble turned out better than you expected. I just wanted to say, there are holding tanks with wheels that could be just the thing for your toilet. The tanks are blue, and can be found on various RV and trailer sites.
I am restoring a 1958
Bubble, the only one I have heard of that late date. I just got the new title yesterday, after having been working on it for 4 years now. What a relief. Now I have added incentive to get it roadworthy. I am still riveting the shell back on the frame. What a major pain it has been, but it has a completely new floor. They obviously never made these things to come apart again. I am also in the process of sanding the interior before I paint it. Then I can start installing the new interior structures I have built, based on the sagging, rotting, smelly originals. It is going to start getting expensive after that, with some new appliances and plumbing. I am still trying to find a "stock" holding tank that will fit in the VERY limited bathroom space. It will be a compromise, probably a marine tank curved to fit a boat hull.
Anyhow, good luck with your new Bubble. Let us know how it is going.