Nice Job on the shop 1:1!

Nothin' like dedicated building space.
Some thoughts on benches.
I agree that 4x8 is probably more than you need. Although I find that benches are stuff magnets, so there is no such thing as too much bench space. The trick is to keep things orgnized and be smart in planning. If you think you want more work surface...build multiple smaller benches.
Here are some ideas I have implimented. Build any benches you make to the same height so if you wanted to push them together... you have some flexibility.
You can also put the bench/s on wheels. Here is one of mine. There are toggle locks on the legs to secure the table when I do not want to move it. Flip up the toggles and I can move the bench heavily loaded, with two fingers. I find it handy to be able to move things around when the job changes. When you want the benches out of the way...roll em against the wall.
This is the EAA model with some changes. I built the center to allow for a drop in C- frame. When I am not "C-framing" out it comes and it is replaced with an appropriately sized insert.
I also like building these with little tool tray extensions on the ends. This way your hand tools are below the work surface and out of the way. Here it is with the carpet cover.
Below: I also built a rolling bench without the trays. This one is nice for assembly. It is about 3x4 and is the same height as all of my other benches. Also on wheels.
Just some other ideas that you might find useful. Good luck.
CD