Just make sure you install adequate angle/diagonal bracing in the walls if you want it to be free standing, just like you would building an exterior house wall without plywood on the outside.
https://www.finehomebuilding.com/2011/05/19/4-options-for-shear-bracing-foam-sheathed-walls
Just use what you have. Put a 2" space between the two boxes and just wire them separate. That way you aren't looking for custom covers.
Use a pc of 1x2 above and below the boxes to support them if need be.
Keep it simple.
Re: Questions on concrete
Sounds like you already know the answer to that one. But.....I'd pour the stub wall below frost line, insulate under the slab well and go with infloor heating.
http://cgi.ebay.com/Portable-sand-blast-cabinet-with-casters-Make-offer_W0QQitemZ9502053782QQihZ007QQcategoryZ26261QQcmdZViewItem
Portable sand blast cabinet with casters. The workspace dimensions are 5 feet x 2 feet x 6 feet
Wow this is a great forum. I've posted some info, hopoefully it helps. I am a carpenter and homebuilder up here in the north. We are just getting dug out from a blast of winter. There are some beautiful garages here and I've gotten some great ideas. I'm into Pontiacs and GMC trucks and am...
The whole secret to this system is to insulate under the concrete slab with 2 inch styrofoam. This allows you to use a smaller heating system (gas water heater instead of boiler) and prevents you from heating the ground constantly. (the ground stays a constant tempurature so you will never...
Here's the ultimate setup. I came across it while we were renovating a local garage. Made in Toronto, Canada. I've been wanting this for quite a while and go back to the website everytime I see one in use somewhere.:thumbup:
Shop Crane / Cherry Picker (Low profile)...
Here's the ultimate transmission jack. A complete lifting system for your shop with a hoist.
http://www.canbuilt.com/products.asp?subcat=40&cat=14#
Made in Toronto, Canada.
http://www.canbuilt.com/images_large/3200LSAP.jpg