I'd be slightly cautious of how many far east manufacturers actually do double butt tubing. Unless you cut your frame up it would be pretty hard to tell, the fact Waltly refused to was a confidence tick in my book, I.e they were prepared to tell me they couldn't do something than say yes to clinch a sale. Personally I'd go straight gauge.
Ti is usually externally butted so you could tell because you could measure. But I understand your point and that's fine. It just might be the reason I don't go with them.
I'm going to thoroughly prototype and test the eventual frame before selling anything anyway
I'd be slightly cautious of how many far east manufacturers actually do double butt tubing. Unless you cut your frame up it would be pretty hard to tell, the fact Waltly refused to was a confidence tick in my book, I.e they were prepared to tell me they couldn't do something than say yes to clinch a sale. Personally I'd go straight gauge.