Good question. It previously gave a formula for a "short term" player, where the jackpot must be positive on bet one.
However, for the long-term player, who can afford to play until the jackpot hits, the hit point is less. I have updated the page to include formulas for both types of players. Briefly, the two formulas are:
j (short term) = m × (1-f)/(1-f+r)
j (long term) = m × (1-f-r)/(1-f+r)
Where:
j = Breakeven jackpot size (with 0% house edge)
f = Value of all fixed wins plus slot club points and incentives.
m = Maximum jackpot (the must-hit-by point)
n = Minimum jackpot (the reseed point)
r = Rate of meter rise