As for dimensions:
Length: Make it as long as you can fit in your shop reasonably. You may find yourself working long cabinet or bookshelf sides, so long is good. Mine is 5' due to space limitations, but 8' would be used if I had the room.
Height is determined by you and what you want to do on it. Many people make it high enough to double as an outfeed table for the TS, but if you are 5' 8" tall like me, and intend to use it for hand planing or routing, the TS height may be a few inches too much, You can always block it up but it is a real pain to shorten. Mine is 32" and my TS is 36". The 32" is good for me for routing, using hand planes and sanding, and it is easy for me to slide a piece of 2 x under my thickness planer so I can use the TS as the outfeed table.
Width is the hard one. The actual top width is what you can comfortably reach across. Monty's table has a tool till opposite the side vise, so his dimensions make it easy for him to drop and retrieve tools from it when standing on the vise side. He has longer arms than I. However, with no till, you can work from both sides, so if you plan on using it for wide pieces, wider may be better for you. Although I have seen some 18" wide, which is excellent for hand planing long boards, 24" to 30" is the norm. Wider is good if the bench doubles as an assembly table.
Bottom line: Forget the "Golden Mean". Its another tool/jig, so build it for what you are wanting to use it for. If it works well for what you want to use it for, I really think it will look good to about anyone on this forum!!
Just another opinion
One caution: Decide what vises you want first, and buy the vise hardware second. THEN design your bench. In reality, a woodworking bench is a surface that holds the vises you need, and their dimensions have a major impact on the dimensions of the base and supports.
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