Don't go for vari-focal, although if the middle band is 0 / planar they might work. Any correction in the middle height seems to be reduced to a ridiculously narrow hourglass which needed head turning simply to follow a line on a page.
I was flying a new type in my old age and needed to be quite sure I was identifying the ATR's overhead buttons correctly. Some of my colleagues were spending hundreds of pounds on tri-focals but that was out of my budget.
I got a 5 quid pair of horn-rimmed ready readers and Dremel'd a horizontal slot out of the middle. Perfect.
I did find some reluctance to making me full size split readers. Spec Savers said they don't do those any more and made me the small rounded readers. I was lucky that I rarely ever needed long distance. Just a touch of CYL correction was nice, but a luxury. I've had a lot to say over decades about focusing with the extraocular muscles. I really annoyed a pal/local optician when I was quite young because I'd report a slightly different angle for the cylinder (astigmatism) correction almost every time I had a check up. In old age it cost me dear.
I repeat this tale whenever I can. I had some very distressing weeks of eye ache and I think found the answer. However, a recent comment on Quora shows people are not open to new ideas. There is something published with the proposal that prime focussing is achieved in youth by way of the extra ocular muscles. If it were true, the following would be substantiated.
I spent a lot of a summer holiday back in the UK with aching eyes and slight defocusing. I sought urgent help but no one could find out what was wrong. The Rivetess had to stand on the brakes for some critter that ran out in front of us and at that moment my eyes relaxed and focussed. I knew what was wrong, and an urgent request for Diazipam gave the muscle relaxant needed for diagnostics. 30 minutes after weeks and back to perfect relaxed focus. It's an odd thing, but when spasms like this get found out, they seem to just dissolve away. I have a friend who was rushed to hospital with a neck that was jammed solid. He'd had a history of it, just now and then. Nursie gave him a huge shot of relaxant and he was fine.