Surface Prep
When fitting a new perfectly flat clutch disc, it's always best to get the flywheel resurfaced perfectly flat too to have the best chance of achieving maximum contact & friction.
If the disc has already been worn against the flywheel before, the ripples of the two faces are probably now matched and best to just give it a clean.
When I swapped from stock clutch to new paddle clutch, my error was I didn't resurface the fly, so the new flat paddle clutch was trying to work on a terribly rippled flywheel surface which reduced contact area, friction, so it began to slip.
also intentionally slipping the clutch at santapod drag strip was the final nail which glazed it badly.
Flywheel mass
Heavier fly provides more smoothing inertia during clutch slippage.
This reduces the juddering cos the inertia is keeping the crank spinning rather than bogging the revs up/down, and provides more initial torque when the clutch bites cos all that potential inertia energy can be instantly transferred straight through the drivetrain rather than waiting for the engines powerband to catch up.
Disadvantage is slower gear changes and rev-matching cos ur waiting for the spinning crank mass to slow down or speed up before engaging to maintain a smooth torque delivery through the drivetrain/tyres to reduce mechanical wear and prevent loss of traction.
Thermal capacity
Whenever a clutch or brake system slips under applied pressure, it converts the components kinetic energy into heat. Friction material has a maximum operating temperature before it starts to degrade/melt and loses co-efficiency of friction. The flywheel & clutch has to dissipate this heat to stay within this operating window. think of em as CPU heatsinks.
A large heavy fly has a higher heat latency to soak/store up the burst of heat and larger surface area to dissipate the heat via convection, conduction, radiation. so they can withstand more abuse for longer (I wonder what if flywheels where also vented/grooved/drilled like brake discs?)
A lighter thinner has a limited capacity to withstand clutch slip abuse before things get too hot very quickly and degrades.
Clutch engagement
Paddle clutches provide a fastest engaging and max amount of clutch friction for a given diameter by both reducing surface area to increase surface pressure for a given clamping force and creating a very hard sharp leading edge using ceramic material to literally "bite/dig" into the soft metal flywheel/PP. This creates an aggressive fully on/off juddering engagement.
For racing applications this is a minor sacrifice cos clutch slippage is only very briefly engaged for leaving pits, full power standing launches and racing speed gear shifts.
On public roads however, you'll be constantly and slowly slipping the clutch very frequently due to junctions and maintaining a small gap during slow congestion.
although the aggressive juddering engagement is funny at first, it will eventually be an annoying inconvenience during traffic.
Organic full-face clutches have a far wider progressive range of engagement between on/off and the choice of clutch material can influence it's performance and wear, much like brake pads.
Wear
The ceramic paddle clutches are harder than the steel flywheel/PP to maintain their sharp biting edge, so the flywheel will wear more quickly than the clutch disc. cost of resurfacing and/or replacing multiple flywheels/PP over a timescale could end up higher than the cost of the paddle clutch.
Organic clutches are softer than the flywheel so the clutch disc will wear out before the metal flywheel. the larger amount of clutch material contacting the surface means it'll wear alot slower in comparison to a paddle clutch tearing the metal flywheel away.
Running cost (£ per year) of replacing multiple organic clutch discs over the serviceable life of a flywheel is prob much cheaper than replacing multiple flywheels over the serviceable life of a paddle clutch.
