Since a few months I'm adding different sites to my schedule to be able to game select better. On enteraction network I encountered some rebuy tournaments that differ from the standard format where you can make 1 rebuy when you have chips equal or less to your starting stack.
Ine format is where they offer 2 rebuys after start equal to your starting stack and 2 add-ons after one hour which are 3x 6000 chips, 2500 starting stacks. Basically I expect the best strategy would be to start playing with no rebuys and then add the 2 add-ons in the break to your stack where you get almost 6 starting stacks for 3 buy-ins.
Another format is tournaments where you start with 500 chips and the tournament has a fast structure. However they also offer unlimited! rebuys, the tournament is a 4K GTD and buy-in is $0.5 with unlimited rebuys.
What kind of rebuy strategy would be optimal and how do you figure out (math wise or whatever) to determine the optimal rebuy strategy for rebuy tournaments as described and for rebuy tournaments in general?