That's pretty much how I do it. I use a galvanized chimney cap (sheet metal) turned upside-down with short legs added. I then have a pan deep enough for a couple gallons of AF to catch the runoff and use a sump pump to get it to the flushing adapter. I have to add a couple more gallons right after I start each engine (one at a time) because the catch pan I use only holds so much with the sump in it.
I warm my engines up first, then drain the blocks and manifolds. That way I know that pretty much all that goes in will be antifreeze. It doesn't take long for the thermostat to open up since the engines are already hot.
_________________
USCG 50 Ton Master Inland/OUPV Endorsement+Towing
1998 278 Vista - Twin 4.3 GLs, Kohler 4KW Gen, AC/Heat.
1999 Yamaha Waverunner SUV
2003 Yamaha Waverunner SUV w/MR-1 HO conversion
