I found that none of the cheaper furling systems was satisfactory. The drums are OK because you’re pulling the line to make the drum rotate, but the top swivel is the part that can cause difficulty. Unless this remains ‘free’, even with full rig tension, the halyard tends to rotate more easily than the swivel, leaving the sail twisted up rather than furled or unfurled.
My advice would be to go for the best top swivel you can afford, (or better still go for a reefing system). If you have to reduce rig tension to make it work, it isn’t really a suitable component IMO.