Yes please, it will help. Nowhere can I find videos on the internet. It is trial by error for a first time cuck like me.
Sorry, it's a little rushed. She let me out for a shower this evening and I asked her to record it for you while I put the base ring on. She said, "ok, but make it quick." So here's a "quick" video of how I put on a 45mm base ring:
View attachment InShot_20200513_235712800.mp4
Regarding getting the right cage, it sounds like your wife doesn't plan to let you out for cleaning very often. If that's the case, I highly advise against cages that are enclosed tubes. Even with breathing holes, those are very difficult to keep clean if you're in them for more than 2 or 3 days at a time. Yes, if you're into taking a 45 minute shower every day and working a bunch of soap down into the tube and making sure you don't miss a single wrinkle and can get enough water in there to rinse it all out, it's technically possible to stay clean, but you'll be infinitely better off with something with bars rather than a molded, flat shape. If your wife prefers the other style, maybe talk to her about more frequent but very short, supervised releases just for cleaning. Going from zero to a week at a stretch is pretty ambitious, in my opinion, and ignores some hurdles I think you're likely to run into that you're probably not expecting now. Avoiding funk with a device you never take off is one such nuance.
Also, I very much second
@jbgenius 's recommendation of getting sizing rings from MatureMetal. I have a set and they were very useful before I had tried enough different cages to know what was going to fit me. Those folks are great to work with, too. I have one if their devices. Unfortunately it allows too much access and isn't all that secure, so I don't wear it all that often, but it's a work of art and my wife likes the way it looks, so if we're going to be out together and I won't be unsupervised anyway, sometimes she has me wear it. Especially if other people might be getting a peek at it!
Last, I recommend starting with something inexpensive, because there's no such thing as a flawless device. If you're anything like me, you will start to notice something about it that you wish was different, and find a device that solves that issue, but then discover something wrong with that one. Start with a device you can get on eBay for $20 or Amazon for $40 or so, and see how it feels. Once you've tried a few, THEN consider something custom, if you think you'd like something more tailored to you specifically. I wish I'd wanted until I had more experience before I ordered that MatureMetal. It was expensive, but reasonable if it would have been my primary cage. If I'd known what I was doing I would have had them make it differently, and I'd be getting a lot more value out of it.