First half of gambit event cost around 6000 stamina to finish with average luck.
It can be finished by most active players without using any stamina restore items.

2nd half of gambit event cost around 13000 stamina to finish with average luck.
Most players need stamina items to finish 2nd half of event.
20-30 full peronamin should be enogth for very active players to finish 2nd half of event.

Players who got 20000+ flowers in first half without spending stamina items are on track.

Spins cost much more in 2nd half but because players burn tons of stamina items in 2nd half players will get maybe 50% flower in 2nd half of event than first half. 50000 flower is not easy to get for free players to get but still much easyer than 150 lightning bosses.