I was hoping to get some feedback from people familiar with one or both of these machines to help me with my first welder purchase. It has been about 15 years since I have welded at all, and was only a novice stick / TIG welder. At the time, I had improved my technique quite a bit with welding plain steel and tubing but never formally learned how to weld or set up the machine. Now I have the interest to learn more, make this a hobby, and I have started an auto restoration / fabrication project, and finally am in a position to buy a welder. I decided that I want one of the Miller Dynasty TIG machines.

Most of my welding will be with 1/4" thick or less material, however, I will also on occasion want to weld thicker materials. I don't ever plan on using the welder in a business or for high volume production. It is for hobby use, but I am willing to pay more for the extra features and lower electrical demand of the dynasty series because I see this as an investment in a piece of equipment that I will use over the next 30 or 40 years. I have a few specific questions:

1) The Dynasty 200 is advertised as capable of welding up to 1/4" steel. What would this mean if I wanted to weld a 1/4" plate in a tee junction with a 1/2" thick plate, or even thicker material? Do I understand correctly that it would only penetrate sufficiently for welding the 1/4" plate?

2) At what point do you really need the water cooled torch / cooling system for either of these welders? Starting out again after many years, I will be very slow at welding. Does this mean that using an air cooled torch and just the welder itself would probably meet my needs until I start welding at higher duty cycles and amperage? Are there any risks of doing this?

3) I would like to hear some feedback from those who have maxed out the capacity of the Dynasty 200 and help me understand the limits of this machine in real world terms. I could justify the higher price of the 350 now if I will need it in the future, but of course it will put a dent in my budget for my project and delay it.

I have just finished building a workshop with two dedicated 230V service circuits. One 50A and the other 80A.

Thank you.