If the clutch slips in a way that there is no gain or loss of rpm during launch, flywheel weight won't affect the launch at all.

Where flywheel weight will make a difference is when you are balancing stored inertia against the clutch's torque capacity. Here's a simplified explanation- generally the clutch's torque capacity is higher than the torque that the engine makes. Let's assume the engine makes 500ft/lbs and the clutch's capacity is 700ft/lbs. When you launch the car, the clutch is going to draw 700ft/lbs…the 500ft/lbs that the engine is making plus another 200ft/lbs of stored inertia energy that will cause the rotating assy to lose rpm. This is where the balancing act comes in- after engine rpm is drawn down to the point that engine rpm sync's up with vehicle speed, rpm ceases to drop and that transfer of an additional 200ft/lbs of inertia energy stops. If you raise rpm or add a heavier flywheel, more energy is stored in the rotating assy which extends the amount of time that the clutch will be forced to slip. When you extend the time that the clutch slips, you are delaying the clutch's lockup to a point farther down the track where the car is traveling faster, which means less "bog" at the point when speed and rpm sync up.

In the end, installing a heavier flywheel or raising staging rpm are just ways of forcing the clutch to slip longer, minimizing the bog. The downside is that after you have lost the rpm and used that inertia energy to force the clutch to slip longer, that spent energy then has to be paid back in full before the engine can recover the rpm that it lost. That inertia energy transfer which made the car launch harder initially now slows the car, as it reverses and some of the engine's power must be used to recharge spent inertia energy back into the rotating assy.

This is why temporarily holding back some clutch clamp pressure at the throwout bearing to prevent rpm loss, is a better way to launch. The initial hit of the clutch is softer as you are not borrowing inertia energy from the rotating assy, but then again you won't have to pay that borrowed energy back either. The softer launch is easier on parts, easier to make the tires stick, and actually quicker as you can now easily extend the clutch lockup point far enough down the track that you won't lose any launch rpm at all. Remember- the car actually gains speed at a faster rate during that period of time before the clutch locks up. After the clutch locks up and the rotating assy is gaining rpm, some engine power is siphoned off and stored in the rotating assy, which means the overall acceleration rate will be slower after the clutch locks up because the rotating assy is being accelerated as well. If you want proof and collect rpm data, all you have to do is lay a straight edge along your rpm graph from the point that the clutch locks up in 1st gear until the shift point. The angle of that straight edge represents the average rate that the car gained speed after the clutch is locked up in 1st gear. Then lay a straight edge from the "0" beginning point to that same point where the clutch locked up...the angle (rate of acceleration) before the clutch locked up will be steeper. To a point the longer you delay clutch lockup, the longer you can ride that steeper rate of acceleration.

My ClutchTamer is just a simple way to temporarily hold back some clutch clamp pressure at the throwout bearing, but you can do it with your foot if you put in enough practice.