Hi Jason,
and congrates on the new scope.
The magnification goes up as the number on the EP goes does. The 25mm you have will give u about 81x mag. a 6mm will give you 336x. (prob to much as it depends on the "seeing" from what I understand anything more than about 200-250x and u will be pushing the bounds of the scope. I cant comment on the EP kit as I am very new to this as well and only have a couple of EP's that I purchased with my scope. Plenty of others will give u better advice re EP's than I could.
Have fun with the new toy.