A hypothethical staking arrangement

[jkkkk]

A friend of yours, Kris, comes up to you and says:

"I know this crazy guy who is willing to give 200 even money on his open ended straight flush draw cracking my top set everytime, I've already worked it out and we have 60% equity for every single time we take this bet. Can you stake me and we'll split the profit 50 50? I only have time to do this once but it'll be some easy money, what do you say?"

You sit back and think for a second and then reply:

"No, it is -EV for me to risk 200 to win 100 on a 60/40 bet, but obviously longterm we would make money'

How many times does Kris have to make this bet, and with what size bankroll, for this to be profitable for us after one session?