I'm trying to add variants for a ski size. We have four 62 63 64 and 65. I want all four to be there, but we are out of 65. I still want it to show as a variant, but I don't want anyone to be able to order it. I set the quantity on hand to 0 but a customer can still check out with that varian selected. Is this a bug, am I doing it wrong, or is this not possible? I'm running smith 4.0.0 dnn 05.06.00

That was not enabled so I did enable it. I went into and added 0 in the inventory management, but I was still able to checkout with that variant, even though I had set it to 0. I did replicate on your test portal. Look at the product better than apple. It worked when all I had was one variant group and they were both set to 0. Once I added two variants, one with 0 inventory and another without, I was able to check out.