Ken,
I have built 3 Hagtech products including the Cornet2. Like you, I had limited experience. I had very few problems building the Cornet2, but I did find paying extra for the pre-drilled, ready-to-go Hagerman chassis irresistable due to my limited ability to do the metal work. I used 2 soldering irons, both pretty cheap, one a 30-watt Radio Shack. This was all I needed and it worked just fine. I tried both .05" and .031" solder and both worked fine as well. I am slow and steady and never had any faulty solder joints. There is lots of room on the Hag circuit boards of the Cornet2 and Clarinet for using a moderate-size soldering tip, but I did find myself wishing for a fine tip when I built the Bugle. I think you will be fine, although I am not familiar with your solder iron. I did the upgraded capacitors recommended by the engineer in his instructions. To me, it would be silly not to do this i.e. not to take his seasoned advice. Oh, yeah...tubes. I got all mine from AES, again as recommended in the instructions. Then I did upgrade tubes, for which there is lots of advice on this and other sites. Good luck, but I don't think you can go wrong with this Hag stuff.
