The amount of event currency you can farm per stamina spent is the same for every map. So on the first map, you might only get 5, but it costs only 10 stamina, while on the last map, you might get 40, but it costs 80 stamina. It's the same ratio.
To give you an idea: I'm still "only" at 890 dumplings. Out of the 2,000 needed to get Lunaria with all skill and equipmentslots unlocked. I do have a big advantage though, but it isn't the level of my girls or being able to run the last map. The advantage is my higher level, giving me a higher stamina cap, which means I "lose" way less stamina while I'm asleep or at work.
But, whether I use my stamina to run the first map 8 times, or the last map only once, the total amount of dumplings gathered remains the same.
So, just an advice: stick with that first map, run it as much as you can, and the first map of phase two when that gets released (phase 2 maps generally give slightly more event currency), and level up. http://harem-battle.club/flower-knig...uide-tips.html has a lot of useful hints for that. Especially the part about how to level up your girls. Use manyus on girls of the same color (to save yourself a lot of gold), and try to speed level at least one of your girls because that improves the quality of the helper squad you get (even the best helper squad gets tweaked down to the level of your highest level girl. Probably safer to also put that "best girl" in your first squad)