Ask yourself this question:
If I were a Google engineer and I wanted to decrease the value of an EMD how would I do it?
1. devalue domains with "how to" in them
2. devalue domains that are long and have multiple words
Google wants authority. How authoratitve is an EMD with howto in it. No one registers a legit domain name with howto in it
I agree with this 100% as far as the EMD importance but I also think that the anchor text from backlinks will help with the long and shorter versions of the KW's plus it should be all over the on page as well giving you a boost in Serps.In my opinion, you only get a boost in Google when the query exactly matches your domain (not just a part of it).
People rank for the partial matches because those words are in the anchor text of which they promote their site, its in their on-site optimization, etc. However, there is no "EMD bonus" received for ranking for the partials, any more than you would have received for a domain that doesn't have the keywords in them at all.
If there is some sort of boost by having a partial match, it isn't anywhere near as much as having the exact match.