The fact of the matter is simple: DMF Amsterdam is the next European DMF, and that's not til SEPTEMBER. Europeans had their shot at DMF Italy, and yes, DMF Amsterdam will put more in the market, but until that DMF, they have no choice but to buy them online if they want to play him. Sure, DMF Boston may surge more into the market, but a) People actually WANT this guy. 100 were given out in Turin, and how many are on Ebay? Everyone that picks them up aren't just suddenly going to spring them up for sale. He's incredibly powerful and people like him. b) You're grossly underestimating the Mini's Playerbase by saying Epics are still "rarer." That's absolutely laughable. It's not even remotely comparable. Even calling this guy a Rare is silly. It's not in the same scale at all.
There are two types of people when it comes to these situations. The ones that know how to make money, and the ones that dont care. The ones that dont care will keep their Mortimers, and/or sell theirs to the ones that know how to make money. The ones that know will keep these to themselves, eat them up en masse and control the market, just like they (we) are doing now. There's nothing you can really do to stop it. Even if DMF Boston puts 100 or 200 more Mortimers into the market, at LEAST 60% of more of those are probably going to end up in collections, or in the hands of the people that know how to make Money. That 40%ish or less percent (which is being very generous) may be your only window of opportunity to get them at a slightly market down price, but even then... those periods wash over, and once they're gone the price will stabilize once again.
Basically, the end all point of this is, something selling for $150 today will not suddenly sell for $25 tomorrow. It will be a very, very, very long time before it does. One DMF will not impact the price nearly that much, so be prepared. Maybe six DMFs.