That's why I said what I did in my previous post on this thread "It's going to take a bit of trial and error. Just start out with low force and gradually increase the force, measuring for a permanent spacing increase after each try. The last thing you want to do is apply too much force on the first try and buckle the stays. "

This is one case where no pro tool will prevent you from using too much force or even give you an advantage during the learning curve. It's going to be trial and error.

Starting out on hack frames isn't necessarily going to help. Hi-tensile steel is far easier to cold set than CrMo or Mn Mo. As the steels get stronger, more force is required and there is less margin of error, due to the thinner tubing. You're starting all over again, with each step up the tubing ladder.

As I said previously, just start with a light force and measure the result. If there is no permanent deflection, just keep increasing the force and measuring, until you get one. Sure, an LBS will have a better appreciation of the general amount of foece required for a certain steel, but even the good ones will start low and build up, they just won't start as low. The only advantage to an LBS, is you have avenues for compensation, if they damage the frame.

BTW, I started out cold setting frames with hockey sticks and measuring results with string and rulers. I did this for several years before going into the business and buying the pro tools. In some cases, the pro alignment measurng tools do expedite the process, which is critical for making a profit. They are more efficient but not more effective.