I have seen those, but never used one. That's the same guy who makes them to convert the OF1010 also. Looks good, but I haven't bothered to try either yet. After a while of stretching the hose fitting onto them, it gets much easier. Brand new hoses, not so friendly, but it does work.
I never have a problem fitting a hose on the oval dust ports of the RAS, DX93 or PS2. When the hose, or better, the nozzle, is new it sticks on pretty well, but when a nozzle is older it drops off all the time.