for the drop rate, use ratemyserver.net database

If you use Bubble Gum use this Drop Rate Formula:
ACTUAL_DROP_RATE = ITEM_DROP_RATE * ((SERVER_DROP_RATE * BUBBLE_GUM)) / 100

e.g. Card Drop Rate is 0.01 then the Formula is
0.01 * (100% * 2 (bubble gum) / 100)
= 0.02 (ACTUAL_DROP_RATE)
so you will enter 0.02 as the drop percentage