Good Morning,

I have tried to do my due diligence in finding an answer on my own first! ;)

I am working on my second tig-welded frame.

For the first I ordered tubing from Ceeway, purchasing a 28.6 externally butted Zona seat tube and 30/15mm chainstays, amongst the other tubes.

I am going to try some different brands of tubing for my next several practice frames, just to get some practice in using different tubing types, and have been researching various types in preparation to order.

My questions are:

1) If tig welding, do I always need to use an externally butted seat tube? I don't have a lathe or mill to make any thicker tubing sections that I could weld into the top of the seat tube.

2) I am going to be ordering some oval chainstay tubing blocks for my mitering jig and have the budget to get one set right now. I imagine that chainstay diameter is planned based on the weight of the rider and stiffness desired, however, If I was going to just use one size oval stay at this point what would be a good "middle-ground" size? For example, I see that Velospec for example, only offers 30x18, 30x16 and 26x17, whereas Reynolds offers 17.5x29 oval/round and 17x27 oval/round (perhaps with others sizes in higher end lines) and Dedacciai has 24mm and 22mm oval/round.

3) Are round-oval-round chainstays primarily used for lugged bikes?

Thank you in advance for you help!
JD