Go 240 if you are undecided. Half the current for the same amount of work. Smaller wire. If you will have to wire a new outlet then meh, maybe 110 not so bad after all. Remember your standard 110 circuit is going to be 15 amps or 20 amps. 20a x 110v = 2.2kw so that's all you can have with 110v. If you use two separate elements you could go to two different circuits and double total power.
I have my oven. Have my 5 gallons of quench oil. Tongs. Rack. Still need to build my twin grinder. Too many other projects. I am going to get rid of my electric boat and GF will sell her boat so I will only have one boat to take care of, maybe that will give me more time. Except darn... I also brew my own beer so that takes up time and I am of course designated plumber, electrician, carpenter, and cook. It sucks being retired. You NEVER get a day off.
I have O1 and I have 1095 and maybe a stick or two of 1080-something or another. A couple of unfinished projects in 01 but I may bypass them for now, start from scratch with the twin grinder and 1095. Not sure. I will do it like I feel it. I made a few barbecue razors in O1 last year. Wasn't all that proud of them, just a learning thing. I didn't expect much, from magnet, charcoal fire and hair dryer setup. They came out razors, just not the best quality razors. It will be better, with a more rigorously controlled method. Meanwhile, oh no, I have a side of cowhide to make into strops, and 20 GD66's to dehorn and hone. Ale to brew, three boats to keep up, two to get ready for sale, and a pickup truck to make inspectable and roadworthy. When you are retired, there are no days off. I hope to get on the grinders by January or February. I may do a quick chef knife or cleaver or something in the meantime, just to get my HT and quench set up with no surprises.