Power bands for a 9/32 7.1mm shaft

I would think 2x16mm small I/d rubbers would be fine, especially with a 7.1mm spear, but if you are concerned you could try 2x14mm or 2x15mm small i/d rubbers instead. I found Spearitco.com in the US to be a good source for fresh bulk rubbers and associated accessories.

I use Rob Allen style Dyneema wishbones with a bead at each. 1.8 or 1.9mm. If you have a shark finned spear you might be able to use thicker Dyneema but mine last year's.

I think two 14mm small ID would be fine.

Regarding your question about 16 mm large ID compared to 14 mm small ID- I have one experience. I bought an Abellan Denton 110 a few years ago. It came with two 14.5 mm small ID bands. A friend offered me a chance to test it in his condo association pool early in the morning before anyone else was swimming. I was amazed to put 5 shots in a group the size of my palm at a range of 20 feet from the tip, but that's beside the point.

I owned a Wong 60" Super Magnum and had been using three 16 mm large ID bands cut at 350% on it. I did back up the butt with my left hand but I do that with all my mid handled guns and had never noticed any excessive recoil from that gun.. But the gun happened to need new bands so I tied three 14.5 mm bands at 365 percent and took it along in case there was time to test it after the Abellan. I think I had my right elbow locked but the first shot drove my left hand hard into my chin and the muzzle rise was so bad that the shaft went under the entire target. I was shocked since I had never experienced this with the 16 mmm large ID bands. So I removed one band. With the second shot my chin was safe but the muzzle rise was still so bad that the shaft hit the bottom of the target. Then my friend had to leave for work so that terminated the test. I wish I had brought along the 16 mm bands so I could verity that the gun shot OK with them, but I didn't. And I never got a chance to use that Wong in the ocean again before selling it. I did put new 16 mm bands on it though since I didn't want to risk the buyer's teeth.

Anyway, there is my comparison. I still have trouble believing it, but apparently three 14.5mm bands at 365% have a hell of a lot more power than three 16mm large ID bands at 350%.