neatness runes not set at start of map

[the benevolent adversary]

the runes you get with neatness can change. not after they are in your inventory but before you actually by the item.
i am not sure all the particulars but picking something off the ground will change what you get (unfortunately the egg trick doesn't seem to work), also going to other maps will change it (i.e. just come back later after going elsewhere, i didn't see a change just going into a dungeon but i only tested that a few times).
it might take a virgin store (one you haven't been in yet) but i am a bit unsure about this as i think i had been into some before (will be testing more as i play a new game).
as for the question, neatness or alchemy, forget alchemy it is a waste of runes! neatness will give you all the crystals you need (just buy all the lame items). even if you want to use trigger you can get enough crystals. i suppose you do have to be a slight bit picky with what spells you put in your book but not much.
my last playthrough i had all the spells i wanted and even a bunch i never used and still had about 150 crystals just waiting for possible use