Sail and rig controls for classic Finns are no real problem. Since the 60s control lines have usually been sided and so banks of cleats on both side decks are common on nearly all Finns. The sail needs to be constantly adjusted so whatever the rig the cunningham, tack inhaul, kicker and outhaul are required. On early rigs (before the early 70s) the outhaul wasn’t adjusted much so this control tended to be cruder. Various solutions to the lack of space for the kicker have been used.
Initially Finns had no kicker, then it was found that a wedge in the boom slot held the boom down better and shortly after an adjustable wedge was devised, followed by a drum kicker winch which was common until the 70s. Nowadays custom levers are used but a drum or kicker lever (pointing upwards not down) are equally effective if rigged well. Elvestrom realised the importance in the 40s of sheeting the boom outboard so almost all Finns have adjustable travellers. These requirements do not change between rigs so setting a newer rig on an older boat is not a real problem.
The introduction of carbon masts and plastic sails with quite different characteristics led to balance problems and to solve this the deck ring was allowed to be adjusted forward. Many Vanguards have been updated to take the carbon rigs, but if a Needlespar mast is used the rig can be balanced well with the fixed deck ring. A standard rake of about 6.8m applies to Needlespar rigs with a little less for stronger winds or more for light winds.