Gaching.

I'd say to do it now, and probably hope for good luck at either Mushroom Shrine or the usual areas. Since Mushroom Shine shells out loads of scrolls a large majority of the time, it wouldn't be surprising if you got a good sum of DEX scrolls (of course, depending on the amount of tickets you have.)

I can see DEX scrolls inflating very quickly, so grab a Store Permit while you're at it too, that way you can merchant your scrolls and such and get good results making money off of the quick inflation.