As it stands, my DeviceLink setup will only work with stock aircraft, so I can't check the brakes, though it should be possible to see where the problem arises just by watching. A track won't be any use unless the plane is installed anyway.
Looking at the Gladiator track again, it is noticeable that the plane rolls as well as pitches down when the wire stops it - this is probably a gyroscopic effect though.
A 'brakes on' landing in a taildragger is easy enough to spot, as long as it comes in fairly level - if one wheel touches first, the gear will possibly collapse, so it may just look like a hard landing. The 'sudden stop' pitch-down from excessive arrestor restraint(?) may occur while the wheels aren't even on the deck - in fact, a perfect three-pointer with no bounce might stop this happening.
With a bit of forward motion on the carrier, it isn't that difficult to land the Sea Gladiator without using the hook. Perhaps trying that with the Avia might be worthwhile too - this should confirm where the problem is,