question, help needed for NFT/Aero build

Hi, I am using 5x5" PVC and designed it for the 4 inch net baskets, yet i've noticed that every hydroponics store seems to not stock them... only sizes i've seen have been:

the 5" net baskets, and 3.75" net baskets.

my question is where i could find 4 inch net baskets, as well as what size drill bits i would need? would i be able to fit the 5 inch net baskets into a 4 inch drilled hole? wouldnt it just ride just like a 1/2 inch high?

You could try to have the 5" fit in the holes. But what i would do is pick out your favorite grow store and ask them if they will order these specific cups. If you have the book to show them it always helps a lot, but you are their customer base, if they will not help you, move on to the next store and try them. This is why i always recommend befriending your local hydro shop owner.

thank you i'm gunna take the advice about my local hydro shop. though now at the same time im starting to believe that they just don't make 4" net pots. i've looked online first, and now my sunlight supply catalog, notta.. therefore my question is, what size drill bit would i need for either 3.75"/5" diameter net pots. lame. and weird.