Hmmmm I'd just go with the bigger tank and the smaller gun. The overall setup will still be lighter and you won't have problems with efficiency that way. Granted the vik and victory are slightly better on air but not by much once you tune your creed properly and get the updated parts.
You can also go with oil only in the creed if you want, but most people don't. Grease tends to work better in some areas, so I use it instead. Plus grease doesn't get fired out of the gun into your barrel like oil does. Your primary gun also uses grease
Not sure what you mean by the feedneck working loose. Some people have had problems securing the neck collar to the body of the gun. A larger oring in that area solved the problem in most cases.
Either way, still a good review.