I encourage you to try your idea of mastering to 1/4".
I encourage you to determine for yourself whether it is better than whatever you are doing now or whether any number of "simulation"(distortion adding) "plugins" will do better.
Buy an old Otari, Tascam or Teac. Actually, when you find such a machine ask the owner if you may "take it off his hands", for free? If you're careful, you may even get someone to PAY YOU to take one! After all, they haven't used it for many years, (Really would have rather had an Ampex, when they did - don't want either now!)and will never use it again - what's it worth? The trashman, for one, will charge "extra" to include such a thing in this weeks collection rounds and it's too heavy to haul up/down the steps(The guy is old!) and even carry it to the curb - which is why he still has it at all...
Most young recordists(And some old ones) have a distorted idea of what running their digital signals through tape will do and not do. Even those "ultra pros" who DO use tape, somewhere in the process, go to amazing "pains"(And alot of cost) to make sure it is doing something "good" for the process, something worth the time, trouble and expense - check out ATR Services, of York, PA, to see the kind of machines they try to use. Far as finding good tape, itself? Even pro's, with money no concern, have had trouble finding such tape since at least the early 1980's.
Again, give it a try! Don't spend much on the project! Don't spend ANYTHING on the project if at all possible! The person with the old machine likely has boxes of old reels of useless tape around that he'll give you(Gladly) as well.
If someone made a brand new tape machine, good as any ever made and someone else made new tape, good as any ever made, ANY "HSN special" Dell, with on-board sound and a "trial version" of any audio recording program would bury it - in every way...
If you could go out and buy a 1963 Chevrolette Corvette, would it be better than a 2006 Corvette? Yes, in some ways it would - particularly if you were a young person in 1963, and couldn't possibly afford it then. But as a car? Today? Don't trade your Ford Focus(Plus lots of cash!) on the '63...
If every good thing said about tape, tubes, film and carburators is absolutely true, it is still no longer possible for most of us to make use of this past technology.
TG