I have a No.1 in 22lr. It is one of my favorite 22lr type rifles, it feels like a rifle. Mine mimics to some degree the No.1B FWIW.
As you know or are finding out, the conversion to rimfire can be done three ways: lower the breechblock via the lifting arm(cut/weld the oem arm or fabricate a new arm), offset the firing pin in the breechblock itself, or use an offset barrel that positions the rim to the centerfire position.
Getting a new breechblock lifting arm out of Ruger without sending in the whole works is a trip, they list it as a restricted part. But what is parted/welded can be restored via welding if ever want to go back to a centerfire. Reworking the breechblock itself looks the best to me cosmetically, but is a harder conversion for most. The offset barrel has not appealed to me yet.
I was thinking that a new barrel would be the best deal, but you said you like irons, and to gunsmiths in general, irons are a hassle to do. Not impossible, but can be costly if you know what I mean. Plugging and sleeving the oem barrel to keep the irons/markings will have a fair amount of labor, so one tends to find that cosmetics probably will cost more than the physcial conversion.
The breechblock lowering via the lifting arm is the easiest to do. Nothing to the work that most gunsmiths can do readily. The ejector mod is not much other than a new hook on an oem ejector, working with a fully supported chamber. You might take some time to choose the reamer.
One might look around for the best deals, some smiths doing a conversion are proud of them. Choose a smith you have confidence in. My plain jane version cost 150 dollars and that was for the barrel.
If I had to do it again, and I might do a lightweight version in 17HMR, I would still use a new barrel. I just think they will shoot the best after all the effort. Not against a nice line job, but the new barrels today are right good.
Some folks like a rifle in rimfire that mimics the centerfire versions closely, guess I am one of them, and finally did the conversion on a No.1.............and still like it.