I've used a product called "Strutz", annealed brass (crushed or rolled) tubing that is the same and definitely cheaper. It was available through Aeroclub in the U.K. (
[email protected]) and I believe it was also available through Roll Models. You can see a review by Stephen Lawson over on Aeroscale (Early Aviation Forum), just search "Strutz". I "scratched" the landing gear and interplane struts for my Roden Alb DIII to add strength and it's great stuff. You get a "variety pack" of various sizes for around $20 US equiv. and it's all useable for struts, cockpits, etc. I highly recommend this product, the package will do several kits and once you have a size reference I believe you can order just the gauges you need. It's been a year or more since I got it, hopefully it's still available.
Cheers,
Lance