While the Rage or similar may work, they are nowhere near as rigid as a real cold saw.

If you are trying to make a living with tools, where your time is money, you will never be ahead by buying tools that are not made to save time.

I'm not saying the Rage saws aren't nice for a hobbyist or casual user, but if you are serious about making this your livelihood and getting into the metalworking business, you really should be looking at a more industrial level cold saw. WAY more money, but also WAY more saw.

I know you mentioned that you wanted to tig the first one, but really, the GTAW process isn't the right fit for this type of work. Basically no benefits in this case, other than possibly spatter removal (nothing a little anti-spatter wouldn't eliminate). GMAW all the way for this.

Welding some stop blocks to your table for setup would allow you to ditch most of the clamps and save 50% or more on the setup time as well.

First one down, time to start cranking them out :-)