We're two years into our conversion, but still haven't gotten to the window insulating stage yet

. I sure
hope insulated shades work well, because that's what we're planning to mitigate heat transfer through our stock windows. We were gifted a bunch of "Warm Window" fabric from The Warm Company and plan to make magnetic curtains just like you described. I've seen a lady on YouTube make some nice curtains for her Sprinter van with this stuff and she said it made quite a difference.
I have tinted windows, and they help somewhat in bright sun, but not enough to keep you from cooking on a hot day. And they're no help at all in winter!
Our ideal temperature is 60 degrees and sunny. We'll chase that as best we can from Arizona to Canada. If your plans include extreme heat or cold, you may have to get a little more creative with insulating big panes of glass. You can come up with a solution for any problem - this is just one tiny consideration out of the millions of other things to keep in mind as you shop for and convert a bus.
I feel like I've detailed your introduction thread with all this window talk

. Back to the point: welcome, nice to meet you, and good luck in your search!