So drill the benchdog holes through the MDF layer. Begin by laying out their positions. You'll want these to be precise, so that the distances between the holes are consistent. The vises you are using will constrain your benchdog spacing. My front vise worked most naturally with two rows of holes four inches apart, my end vise with two pairs of rows, with four inches between the rows and eight inches between the pairs. Because of this, I decided on a 4" by 4" pattern.
I live in VA and my workshop is an unheated, uninsulated garage. I work out there year round, even when temps are below freezing. I can't say it's comfortable in the winter (or when it's 100 degrees with 95% humidity) but I haven't had any major issues. I have had some big box green wood warp on me after I built a couple bookshelves and brought them into the house, but that was more a factor of the green wood than my "shop".
The Cape Ann Shed was designed with coastal New England in mind. So yard work may feel like you’re actually on vacation. From Cape Cod to the beaches of Maine, you will find a Post Woodworking Cape Ann shed adorning the yards of thousands of homes. It’s a popular style with our customers – whether they make their home by street or by sea. An affordable choice for an outdoor structure, the Cape Ann brings functional elements with nautical appeal.