We are always needing a trench. I used a mini track loader with such attachment some time back, and though it certainly is no real trencher, it did the job pretty dang good. I think with all our stuff going on, I might like to spot one for our CTL but not sure what to look at or for. I'd want to get to 36" min with some authority, and I'd say a 6-8" trench is fine before we go to the excavator. Reason I ask is someone grabbed a bushhog for the CTL and I had to eval to realize our 299 had too much flow for it, and I believe it was bypassing and heating the oil. The solution was to reduce rpm thus reduce gpm to that mower. Not much of a fan of those mowers anyway but it did stuff....lol
If you have high flow on your CTL, you want to make sure you get a high flow trencher. I would also check the PSI spec on the trencher and compare to your CTL and make sure they will play well togther. I bought an asphalt cutter that was high flow as is my machine, however the attachment was speced to 3000 psi and I was pushing about 3500. Worked for a while, until it didn't.