I have just completed upgrading my DM6 snare drum, using a RolandMH-8 PDX drum mesh head.
To make it work, I had to remove the inner ring of the hoop to make it fit over the drum base and open up the lug holes outer walls to clear the way for the securing bolts to pass it unhindered.
I then pressed the mesh head hoop into the original Alesis hoop, lining the opened holes in the mesh head with the lug holes of the Alesis hoop. Press firmly, it is a tight fit.
I also made up a hoop as per a video I found on the net (Medellie drum conversion), using builders' metal tape held together with insulation tape wound tightly over the entire hoop that fits snugly into the base of the drum to raise the head height.
Using foam sealing tape, i raised the trigger plate and then I also pasted more of this tape onto the rubber mat (which I trimmed to the size of the plate) on the plastic and metal sensor disc to form a raised bed on which to drum. The combined Alesis/ Roland mesh head/ hoop were the fitted with longer bolts and I used nuts under the base to relieve strain on the plastic thread.
I attach a pdf document I compiled to illustrate what I did. mine works perfectly well, with the normal drum sound obtained from striking the head on the foam bed under it and the rim click sound is obtained by striking the head near or on the hoop that was inserted to raise the head height.
I hope you find my conversion useful.