Don't sweat these guys blowing smoke. They insist they are right all the time, and bash anyone not in their narrow view of what is right or acceptable. They love to be rude and bitter in their responses to new people on the forum, and bicker with one liners to pad their post count, in an attempt to validate their bitter responses and "extensive knowledge". They typically throw out either "bah, marine application blah blah stock factory blah" or "need more info, blah blah, vessel length, deadrise, blah blah, oh, yes of course that engine you mentioned in the first post will only require 87 octane". Humorously, whenever I post a question with detailed information about my boat, engine, etc. and what I've already diagnosed and tried for a solution, I get no responses from the post *****s.
I see no reason why your idea won't work. I also see no reason to do it that way. Personally I would just get the appropriate bracket and hardware to make the Alpha drive work, or better yet go back to a Bravo. Merc provided a system that works automatically and required minimal maintenance. I don't know of any better ways. if you have too much cam for a Alpha drive you have no option except to start in gear so the point is moot, but if not the case just use the interrupter switch. It's simple and it works.