Steven,
I am using a Silver crank in conjunction with a Mountain Tamer (
https://abundantadventures.com/mt_triple.html), which can be used with any crank without modification with a 74bcd that requires chainring spacers. I have used this set-up on two different tours (about 400 miles on GDMBR, 2800 miles riding to Alaska) without any issues at all, which I mention as evidence of real world practicality/reliability. I don't know, availability may be an issue?
For kicks, I did experiment briefly with the Mountain Tamer in quad mode. It did work but I abandoned that set-up as too fiddly (as I recall, I had to modify a Silver bar-end shifter and the cage of a Suntour Cyclone derailleur to just barely be able to shift all 4 rings) and it was confusing. Now, as I write this, having a 26t between the 34 and 19 on the last tour almost makes me think the quad might have been worth it? The 34/19 shift always worked both ways but I didn't really like the jump. Then again, I really did need that 19/36 combo, not just once or twice. Around town, as a quad it was total overkill.
I'm one who loves playing with my gearing and hates experimenting with handlebars.
Bill S
San Diego