Just a caution on the 1500 series based on my own neophyte experience: The reels are great for 35mm, but I found for 120 with its thicker film, the 2500 series is much easier to load. Frankly I had a lot of problems with 1500 series reels and 120 until I found a Jobo article by a fellow who'd spent a career using the machine for developing, doing well over 25,000 rolls of film in short order, and he stated categorically that he used the 1500 for 35mm and the 2500 for 120. I had tried the 1500 to save on fluid, and quickly switched back to the 2500. The 2500 reels and tanks are more expensive, but just much easier, and they work fine for 35mm as well. I'll load 6 rolls of 120 (2 per roll) into the big tank, and it works wonderfully. Biggest problem is in my "drying rack" space. Before getting my Jobo machine, I rolled these on a Uniroller.... but that didn't work nearly as well. But you can use a 2500 tank for hand development. You'll need a different lid and cap, but it can be done: I run the final rinse by hand anyway when doing C41. Is it a tad awkward? Sure. But not inconvenient.
I find the red film separator clips on the Jobo reels work very well at keeping two films separated on a reel. I've never tried taping 2 films together, but I guess there's a zillion ways to do this.
Good luck! and have fun.