Hey Copa, just found your thread and read the whole thing. Everything looks nice. Keep it up.
I would offer some advice on your building, BUILD BIG. Build for overkill just in case you need the space later on. When I first started, I built a 30x40 shop with doors that were 12'X10'. At the time I was pulling a small trailer with a GMC 1500. I ended up getting an 18' foot trailer and later on a crew cab truck and the shop was 1.5' too short to fit it in. Consequently, We had to disconnect trailer everyday. My dad did tell me in the planning phase to do 30'x45', but what did he know, right? I saved some money and now wish I had spent it. Also, I just ordered a super lawn truck that is 10'6" high and my shop doors are only 10'. No big deal, we will just back truck up to the doors at night for security. But I'm sure you've already thought of door height since you have those trucks.
The last thing I would tell you is your bush trimmers on the weed-eater racks may need some attention. The trimmer end is heavy and you may want to wrap the shaft with something to keep the racks from eating into your shaft. I found this out the hard way over time. Maybe use something like pipe insulation and electrical tape.
That's all I have for you----keep it up !