We’re using an 18-gauge brad nailer (see this and this) to attach the tubes to the wood frame. We thought that would be easy. Wrong. In our first attempt we got about 15 tubes up before half of them fell off and went rolling across the room. In that system we only attached the tubes together and every fourth tube to the frame so that the tubes could be arranged organically. Although we got the organic look, it just wasn’t strong enough to support these heavy 25 lb. tubes.
In our second attempt we nailed “the heck” out of the main supporting tubes, but it still felt weak. We didn’t have the confidence that this system would still work once several rows of tubes were installed above the first row.
After a lot of time scratching our heads, we got the idea to install plywood strips to our 4×4 structure that would allow us to easily brad nail all tubes in all positions (see image above). This created a substantially stronger base while allowing for the required organic arrangement. It worked splendidly.
We find that every complex problem takes at least 3 tries to get it right.