I've heard of people having issues with returning to the inlet, but never actually talked to one of them
I kinda think it's an old wives tale or something. Plenty of fast, successful people do it and run just fine without issues so I tell people that they should make their decision based on plumbing. On a long car, you'll save some bucks on hose by sending returns to the inlet. It really simplifies the plumbing in most cases. There's a dozen or more ways to plumb returns lines on every setup and they'll all work pretty good.
As long as you keep in mind what is going through the hose and when, you can plumb accordingly...
Main pill or idle check: It's a fire hose all the time the motor is running. If you tee it with something else, have it blow THROUGH the tee, don't branch it in on the side and force everything to do a 90 to get into the hose.
Secondary: It flows very little and only at an idle. Tee it in and branch it if you want.
Pump saver (on a K-Valve): It only works when the throttle is closed and high engine RPM. Plumb it back to the top of the hat distribution block if you're blown and keep those strips cool and lubed in the shut-down. That's where most blower wear occurs. It'll also save you returning it forward and being into the blower belt.
Shut-off return: Because it's blasting at full line size, it won't hurt to run it into a branch...pressure will not build to a level that will ever hurt anything. It certainly won't affect your tune-up! Unless you're not running one of my over-center spring brackets, then look out
Thanks for posting the pic and the link to that, I appreciate it.
High-speed: It only works at the very top end and has very low volume. Teeing it together with other stuff is not a problem.
Spud