FWIW,

One benefit that you can't put a price tag on is experience. With any of the rental options you mentioned you gain team experience. They know how to set the car up and make the needed changes. Most of the rental programs are structured so that you show up with a helmet bag, strap in and go. The car is already prepared, set up and staffed with crew.

It seems to me that you are looking for a bit of a DIY type approach. As with any DIY approach whether it be tiling your bath or whatever, you might be able to save yourself some money. But if you do it wrong, you will end up costing yourself more money than if you had just hired someone. Seems to me that you'd prefer to use your own equipment and "buy" some experience/knowledge. I'd suggest you hire an experienced person and work out an arrangement to point/keep you headed in the right direction. There's a number of people who will be happy to take your money and blow smoke up your behind so make sure you choose well.