I used some Vasoline, and had a female friend with smaller hands slide the "doughnuts" on (nothing like hearing a gal say "Whoa, we need to use some more Valoline..."). For now I tied the two doughnuts together with a real heavy-duty ziptie, will use a stainless bolt/nylock nut/wahers combo as a permanent tie.

The booming got a little beter with time, the ecu upgrade and higher octane full changed the sound a lot !!!