Why bother? I use both S&W 15-22s and .22 ARs in speed events. The key to speed is tactical reloads not the HO lever. While the HO on the 15-22 works fine with its mags I just run the BDM mags in my ARs till I feel I am around 20-24 rounds fired, then I switch mags. The steel lip BDM mags are the best there are in .22 ARs. Getting 100% reliability in the mags is more important than the HO lever when on the clock. I do the same on the 15-22, I don't wait for the mag to go empty before I switch.
That follower will hold the bolt back but will not trip the BHO latch. When you remove the mag the bolt will slam forward. I have the cmmg BHO and have mags with those followers and some from cmmg that work properly (sometimes).
It's nice to have the BHOA so you can lock the bolt open manually.