I think I know how to get it, but there's no incentive for me to
solve it, maybe someone else will:
Relative to the total bet, level 4 has a 2x paytable, level 3 has a
1x paytable, level 2 has a 0.5x paytable and level 1 has a 0.25x
paytable. For example, for 9/6job the 1x paytable is
800,50,25,9,6,4,3,2,1,0. Find the ER and Var for level 4 with 2x
paytable. Now, work down to level 3. Find the hand probabilities for
the correct level 3 strategy. Level 3 ER is prob x (win + level 4 ER)
summed for each winning hand plus freeride x probability of losing x
level 4 ER. Level 3 Variance is prob x (win - total level 3 ER)^2 +
prob x level 4 variance summed for each winning hand including the
losing hand plus freeride x probability of losing x level 4 variance.
Now, repeat the same formula on level 2, then level 1, and you will
have solved for the total ER and variance.
There's a slight approximation in that every time you get a freeride,
you revert to standard strategy, but I don't think that would
introduce much of an error. If you insist on perfection, you can
split it into hands with freeride (using standard strategy) and hands
without using the appropriate level strategy.
Kudos to anyone who can solve it and megakudos to anyone who can
derive the min risk strategies.