i'm pretty f-aar gone...almost to the farside.
'egg-crate' is what they call a plastic grid for fluoro-tube fixtures as a light diffuser - don't know why, as i see no resemblance to actual egg-crates . it's used widely as a prop with seed trays. you prolly use it already.
i add 2tsp 3% peroxide per gal - to keep algae at bay, since i use large water quantities for wicking. ok to use with seeds, helps with dampening too.
if you're worried about contact, adding a trailing acrylic wick to the pot helps (half curled inside on bottom, half outside under a pot covered by the pot) - it'll compress under the pot bt will be in full contact with the mat.
i stumbled on the idea in african violet forums, after i got more then 15 AV's to water...
and i read-up on bottom irrigation, semi-hydro,etc. i do some extra stuff - prolly should pop a sep thread for detail, if there's interest. but basically since i am concerned with too much dampness on the bottom , i take coir-matting and make a little liner and then stuff the soil mix in it. it helps with aeration bottom/sides + it wicks and rewets very easy too. i often put it on top as mulch too: easy to flip up to touch the soil unlike with other kinds of mulch.
there's more to contact (pun intented): you could cut out a good wide circle in the bottom of the pot, easy to do especially if it's very flimsy. then stuff a little flat wad of same coir matting (what they use for wire baskets, but you can get it by the foot on the roll): aeration+wicking. if you plant your pots yourself, you can do that better - like a little liner on the bottom, will help to keep the soil in too. i do all the way up to sides too: when you lift for repot - no root disturbance, nothing falls out. coir matting wicks great.
but enough about me.
