Root plug sizes for nft?

[southernstyle]

Im setting up A nft system for greenhouse lettuce and need to know the width of A root riot plug. I like the round plugs because I am using pvc and will drill A round hole to insert the plug. I want the plug to fit tight in the hole.

I have used 2" net pots in the past but with 2000 plant sites, netpots and soiless media are unpractical. I have seen the gullies where the plug goes through A square hole and sets right on the bottom, I was quoted $4 per foot for these gullies and the total comes to $8k to outfit my greenhouse with the proffesional gullies.

If anyone has some root-riot or equal plug I just need A maximum diameter so I can start drilling holes... I know, I know, Why dont I just order A bag? Because I plan on purchasing A case of 4k plugs and dont want to drill the holes too big and have to trash 1,000 feet of 3" PVC pipe!

Thanks A bunch!
-SS-