Here, let me spend some of your money:
78-17 Yamaha TW200 Barnett Friction Clutch Plate kit -5 Plates (Fits: Yamaha TW200)
Vesrah Heavy Duty Clutch Spring Set SK-206
Seriously, nice heads up r.e. the Lucas Motorcycle oil; I would have tried it if I saw it on the shelves.
The clutch upgrades have gotten good reviews by members here. However you would have to scrape off the old clutch cover gasket, something I wouldn't wish on anyone. Just the stronger springs, or fifty cents for 4 washers under OEM springs might increase engagement forces enough to compensate for the slippery Lucas.