I went back to doing the swingweight and assembly myself. I will bring it in for loft/lie afterwards. Reason I decided to do the assembly again is because when I pay a "reputable" builder, it's never perfect. Whether it is leftover epoxy, or a crooked grip or shaft logo. If I am paying(which isn't necessarily cheap) I expect it to be perfect.
The only piece of building equipment I have is a small digital scale and a good swingweight scale. The swingweight scale is something I've used more than I had thought I would. I don't think you will need to invest a ton of money into the equipment if you take a minute and figure out what areas of the clubmaking process you don't mind taking care of and which areas you don't mind paying for. For me, loft/lie I don't mind paying for because I don't think I'll ever get my money out of a machine.
Stuff like sandpaper and other consumables I assume most people have laying around, and as for tip weights and the like I just order as I need them.