If you use a 130/90 the height is the same. If you use a 130/80 you might want to check the load rating to see if it matches the stock tire which the 130/90 does. The narrower tire makes it easier to steer at low speed.
Hopefully the cancer was caught in time to eradicate it. Sometimes you wonder about why things happen the way they do. Best of luck to your wife and you!
If you do a search, you find a discussion of this. I bought some caps for my 89 several years ago and I posted what I got. I'll take a look tomorrow and see if I can find the numbers. You can buy copper core wire from an auto parts store.
I haven't ridden in a while due to health issues but I hope to do so this year. I probably will give my bikes some needed TLC and sell both of the Ventures. I hope to hang on to the Kawasaki for a while longer but I'm almost 80 and the years do catch up to you.
On my Kawasaki, I used a broom handle pushed against that inner tube to hold it enough that I could use the impact to tighten the lower bolt. I replaced the seals in that bike 3 times. I haven't done that job yet on my Ventures.
I (79) took 3 Pfizer shots and got covid last Jan 2. I woke up with a bad cough and fever set in later that day. I took ivermectin. The next day my fever was high and I felt terrible. I took another ivermectin. The 3rd day the fever had subsided a little and I was feeling better. The 4th day the fever was gone and I felt almost normal again. The cough lasted about 3 weeks and my sense of smell gradually came back still not quite back to normal. My wife (63) who refused the shots caught it from me Jan 3. Her symptoms were similar to mine but her cough wasn't as bad. First time for both of us.
I think most motorcycles produce little current while idling. Letting it idle for 1.5 hrs is enough to drain the battery. Remember the headlight is on and sucking lots of juice. It's typical I think or that has been my experience.