I have not used an Artar or a Ronar focused at infinity where the focal length was much less than twice the long side of the negative. For example, in 4x5 I would use an 8 1/4 inch (210mm) or larger; for 8x10, a 19 inch (480mm) or larger, etc.
If you stop down to f22, or less, you probably can use shorter focal length lenses and I am not sure that twice the short side of the negative wouldn't work as well as a minimum length. But, I haven't tried that, so I can't say.
Given the limitation in focal length for the format, I can't see much difference between a modern lens and an Artar or a Ronar in the same focal length. The only concern being having enough bellows extension for the longer focal lengths.
For focusing at distances shorter than infinity, you can use shorter focal lengths for a given format. I havent tried it, so I cant say how much shorter, but, since you would be expanding the image circle, you would be increasing the diameter of the distortion free center. That is, after all, how these lenses were designed to be used and in that use they were described as having zero distortion. That ought to be pretty sharp. If you look at the old brochures, they were rated for the size negative they would cover, without movements, at 1:1. The 19" Red Dot Artar was claimed to have zero distortion for up to a 20x24 negative.
If you need a long lens in your format and you are not bothered by a slower speed lens, then an Artar or a Ronar will get you something very sharp with excellent color and contrast for less cost, bulk and weight. Just remember that, if the lens is in a barrel, the cost of mounting it in a shutter is not cheap and price it accordingly.
With a 12" lens on my 4x5 speed graphic, my bellows is maxed out.
