I've been using the methods set forth in brightstar's writeup. In case your not familiar, there is no MeOH used and amalgam is done with water prior to dripping in MeNH2 and ketone (both in IPA solution). As a matter of fact, they're not dripped in at all, they are simply added.
Here's my point. I've had it boil over. That's only Al, HgCl2 and H2O. Evidently this does not involve the reduction of alcohols (if it did we would all be using Al/Hg to reduce Ephedrine). I that the lack of vigor is probably due to pour amalgamation (i.e. bad or insufficient amounts of Hg Salt). When it has boiled over, I believe that their was an excess of Hg Salt. The eppervescence is caused, I believe, by H2 produced during the process. This is after all a reduction, which gives off H2. I would be concerned more with lack of a reaction more than too much of one. Next time I'm going to set up a reflux (which was not mentioned in the Brightstar writeup), make sure that I have a good amalgamation in progress and then start dripping in ketone/Nitro in MeOH so that I can nail down all these question I have about this procedure. I certainly have not obtained good yeilds (sometime none at all) and look forward to seeing the fruits of my labor. In the meantime, chemistry is still more fun than just about any other investment of my time and money.