Evanix Rex Rifle ?

I am looking for some opinions on the Rex rifle. The Gamo model is nice but to long for me. I like the shorter 20” barrel model so it can be backpacked and easily carried in the woods. The .357 looks promising and the .45 has me concerned whether it can preform with the small air supply. YouTube has some info on the .357 but not much on the .45 model. Any info from owners or opinions would be appreciated before I place my order. 
 
I have the Rex rifles both in .357 and .45. The .357 worked fine right out of the gate with several different pellet sizes and weights. The .45 had some issues with a tight chamber and it did not like bullet diameters over .455" very much. I had to slug the barrel and found it needed slightly smaller dia bullets, so I picked up a smalle hand press and bullet sizing die in .454". Now the Rex works like a charm. The .357 I shortened a spare barrel to 13.57" and made a full moderated shroud for it. It's less powerful than the full sized rifle barrel, but more powerful than the pistol. The power/shot count drops pretty fast, but that's the price you pay for a small tank, and typically smaller compact gun. I really like both of mine a lot.

Here's the vid on my Rex .357 SBR (Shorter Barreled Rex). You can look for the Rex .45 rifle resized bullets, in my video listings if you want...

https://youtu.be/AEwLJlT6YNI