Well Kwikfish are a fun thing for sure, there's nothing funner than having the rod bury and landing some monster kings.
My opinion on hooks would be to switch to Gamakatsu trebels. Obviously matching size of hook to the size of kwikfish. I've never personally tried the extended chain on the kwikfish but I could only imagine it would help the odds.
As for tuning, certain kwikfish don't need much tuning, ya know the ones that seem to catch all the fish. I personally tune check the tune everytime I rig one up, and especially after landing a fish.
As for filet size I think RT is right on the money for the 15's and 16's. Although too big of a wrap will kill the action. One might note the depth of the meat on the rap is crucial also. The bigger sardines sometimes require a bit of "shaving" the depth of the meat to make them lay flatter to the kwikfish and the skinnier the depth of the wrap the longer the wrap you can use.
Another thing I'd recommend is using tuff line as a mainline and a mono leader when running kwikfish to get away from the stretch in mainline and secure a better hookset.
Just my opinion, but RT you're right on the money in my book! Sounds like she needs some attention, ya know the kind you get at the mental office!
Keith