lol great idea for the rough layout! i suspect someone's into crafting over there
it's now going to drive you partially nuts hunting for specific rocks to full-fill your paper dreams.
regarding the osmolator... i'd never hesitate to recommend one. i've owned 4 different units and three were bought used. they've never failed on me once and one i even dropped the controller unit into water and dried it out (was ro/di mind you). I try to topoff onto the sensor so it sorta keeps it clean(ish) automatically.