2. Did I mention the rain here? How is your shed built? Are flooring and walls sealed to prevent water blowing and leaking in? When we get our summer thunderstorms the winds can whip up the rain pretty good and I even have to make sure garage door is closed sometimes. The shed??? Yea. it gets wet inside no matter how much caulk I use on floor gaps. Mine is on slab and shed not really designed to be waterproof. That being said, even if I got floor sealed it still lets some water in where walls meet roof. Not lots but makes for extreme humidity (or dew point if you prefer) levels.
A woodworker's workbench isn't a table, it's a work-holding system. It's not something you set things on top of, it's a tool that holds your work. Where a worktable might have a machinist's vise bolted to its top, a woodworker's bench is built to accommodate a number of different workholding mechanisms, such as bench dogs, planing stops, hold fasts, or board jacks, and will usually have one more woodworker's vises integrated into its structure.
I don't see anywhere you mentioned the over all length of the bench top. A piece of 1 1/2" x 25" x 8' glued edge oak at Lumber Liquidators costs $192 including tax. Two piece is almost $400! Would that be better if I use two IKEA 1 1/4" x 25" x 74" solid Beech ($99 each plus tax) on top of a layer of 3/4" Birch plywood. That would be 3 1/4" over all.
As I was handling the 2x4's, during the routing, I realized that I really wouldn't be happy with the look of the bench, if it were made from these unfinished boards. They had stamps, pencil marks, and more importantly, incipient splinters left by the saw, none of which I wanted. And I was remembering what other shop furniture made from unfinished pine had looked like, after a few years in the grime of a shop.
Synopsis: No room in the garage? Basement not an option? Consider what Ken St. Onge did when he needed shop space: He bought a prefabricated shed and converted it into his full-time woodshop. Because a pre-built shed doesn’t need a cement foundation and is built in a factory, it’s much less expensive than building an addition or stand-alone shop on your property. It can have taller ceilings than a garage and bigger doors than a basement, both big pluses for a woodworker. You can put a shed just about anywhere, too. Here’s a soup to nuts look at Ken’s experience, so you can gauge whether a shop in a shed is right for you.