If you're going for smoother shooting, stick with the stock 16mm & add a 9/16 black. If you're looking for power, you can step up to a single 20mm (when looking for more power in a single band, I use a band 1 size shorter... i.e. 18mm 120cm band for 130cm gun), I've used mean green hi-modulus bands as well as blue-coated white bands with good success, but because of my personal preference I've gone back to using thinner, smoother bands. I personally like Euros for their quickness & smoothness so I decided to use the lumber guns in my artilery with the hi-mod bands.
Yup, the 2nd band goes through the hole... unless you have an open muzzle
Personally I don't like over-powering euro guns just because their narrow diameter & light weight gives it some mean recoil action - much much more noticeable than a similarly loaded riffe or hybrid. Putting some track down on the gun works great & helps alleviate some of the shaft flexing issues associated with extra power.
Corrosion hasn't been a problem, but I've found the muzzle to be very brittle & of not good quality. First time I ever used it, my muzzle was busted by the tiny fins on the Riffe euro-shaft. I was very upset, but figured it'd be okay since I can just convert it to open muzzle anyways. When I went in to the store, I saw 2 muzzles that had also been broken(not sure how) & were in for repair. My thinking is that the aluminum muzzle is strong, but relatively brittle in some parts. For example, I've used mini-finned shafts in plastic muzzle guns & found marks where the tabs or crimp had hit the muzzle... but no breakage in any of them. About my 3rd shot, I looked at the muzzle & noticed that a nick had been taken out of it. i was perturbed, but continued to dive. 2 shots later, I was reloading & noticed that it was completely broken through! Oddly enough, I had 2 brain shots in a row with the broken muzzle on the way back to the boat! Maybe the shaft was hitting it the whole time? I checked to ensure that the shaft was perfectly straight and I couldn't find any flaw in the system.
I'm very disappointed because of how much I spent on this gun, but instead of wasting time, I went home, put an open wong muzzle on it, new track, OMER reel, & I was back in business. The major selling point of this gun is the connection between the trigger frame and the barrel, not the muzzle, so I'm still satisfied with it... just disappointed in the design. Only time will tell what the long-term results will be...
Overall I like this gun. I love the look of the barrel & it's a really nice piece of work. Would I pay this much again for a euro? No. With a 120cm Alluminum, couple tracks, new muzzle with line guard, couple sets of bands, RIFFE euro-shaft, reel, $30spool spectra, etc.... it really hurts & I could have bought a nice hybrid for that price and still had enough to buy some new fins... However, despite my cognitive dissonance, I appreciate a good gun & won't be getting rid of it anytime soon
Click the picture in my siganture to see it. It's the modified gun on the top.