Bruce, I've read some threads where owners considered a change of belts to be a huge challenge. I also swap grits all the time. I think if you do, it becomes a 3 minute max of taking off the belt, and swapping to your next grit. No biggie, and fully allows you to benefit what one can do for you. Like anything speed comes from the doing.
At 30 seconds you could do a You Tube video, and based on speed alone, it would be viral. You would be semi riche... :-)
I generally buy rolls in bulk, and cut out my own strips. A lot of paper places offer them. Price breaks down to a few bux a roll, and what I get is X or J heavyweight backed, and lasts about 3 to 4 times longer than the crap
SuperMax sells for MUCH more.
If J weight can be gotten for cheap, it is superior in most cases, and usually offers 3 to 5 times the life of X weight, and all of it is a lot longer life than what you get from the name brand material. So if I bought 3 rolls of the J weight I linked to I'd be at 30 bux, and have 3 belts that will outlast the name brand stuff by a LONG margin, fo almost half the cost. Easy Peasy.
Mine are 109"L x 3"W. I can't copy the pic showing angle for mine, but it's in the owners manual. I have a few pieces of hardboard with the angle cut onto them, and use it as a place, and slice template when I need to ready a new strip. If I use that J Weight material I only get one belt per buy, but i get some really nice 3" wide material that is awesome for making sanding strips, and sharpening strips from on the offcut between my needed 110" and the 130 I get.
None of it is Rocket Science, and it just saves you $$$$$ and gets you better product.