Unless SP gives temporary quest or freebie videos on the last day of the event (which I doubt so), no way to get Valor Dragon for free.
As for finding gems, must go past 2 x 50-coin cells, 2 x 75-coin cells and 2 x 100-coin cells before reaching the first 150-coin cell.
Which means there are only 6000-50-50-75-75-100-100 = 5500 coins available (if not buying more coins), so can go through 5500/150 = 37 x 150-coin cells to find the gems. Maximum 37, but could be less if need to backtrack and such.
Basically need to skip the tutorial so as to go by the cheapest way to find the first 150-coin cell and start from there.
I would rather save up and see whether the next few events can get L dragon for free.
Thanks for the maps.
Grid coins tally:
Starting -- 150
Collection -- 600 x 12 = 7200
Quest -- 600
Freebie videos -- 350 x 8 = 2800
Total 10750 (30 short of getting Black Magic Dragon)
Unless got another way of getting grid coins without buying, can't get the L dragon for free. Or did I miscalculate something?