with a rotating mast, and a conventional gooseneck, there are too many moving joints for it to work as intended... the boom kicker being "spring" loaded may have a tendency to turn the mast sideways...
with the boom kicker mounted to a fixed mast, the boom is the only moving part and it is controlled by the sheet and wind pressure, which swings the boom from one side to the other... this is the normal workings of them, with or without the boom kicker...
but with a rotating mast, when the boom swings to the side, the pressure at the foot of the boom kicker, as its supporting the boom, will push against its mounting on the mast and cause the mast to shift in the other direction.... it puts a kink in the works.
the PO of my boat installed a boom kicker without doing his research... the boat was equipped with a rotating boom, and the spring pressure of the boom kicker wanted to turn the mast on its side, rather than keep it in its normal position.... and it doesnt matter where the extra joint is, when there is one, the springy boom kicker puts a kink the works and it DOES NOT work as designed.
in my case, it was easy enough to modify the gooseneck so it doesnt rotate, but unless you either have a gooseneck that ONLY ALLOWS the boom to swing WITH the mast and NOT independently of the mast, your problem kind of rules out the boom kicker option... unless you can either fix the boom to the mast, or fix the mast to its base so its a non-rotating mast.....
and as for needing or wanting a boom kicker, I still prefer the topping lift over the boom kicker.... Ive thought about building a telescopic "boom stop", to be used in place of the boom kicker, to prevent the boom from dropping too far if I should release the halyard before the topping lift is tensioned.... this would eliminate the springy boom caused by the kicker and minimize the use of the vang.... as it is now with the boom kicker in place, I have to have the vang snugged all the time to keep the bag out of the sail, even if the wind isnt blowing....