I don't recommend a catch can, mine had an internal (invisible) screen that clogged which built back crank case pressure and blow my dipstick out and dumped oil EVERYWHERE in my engine bay. Luckily I happened to be at a gas station in the middle-of-freakin' nowhere to get oil, otherwise I would have been completely screwed. I still need to replace my hood liner. Took me a minute to figure out that it was clogged despite being empty! Now I just run a hose down into my frame rail, it doesn't leak enough oil to be concerned about environmentally IMO.
Also worth noting that I started running 20/50 oil this summer and my overall consumption has dropped dramatically, like almost nonexistent now.
If it was empty that should've been. A sign that something was wrong. I've got catch cans on 2 rigs currently. If I ever drained them and they were empty I'd be terrified.