I like the sound of the pressure relief hole. I will pop in and putter around.

The closest HD to us is terrible. If you can find anyone, they usually will hear the question then turn and read labels. Uh. I already did that, I was looking for a little clarification... it's also largely staffed by high school students or recent grads so not a lot in the "experience" department that we used to go there for. The 2 exceptions are electrical and plumbing.

As far as HD goes, I would check on their website. Sometimes you can get connected to an employee at a different store that might be more knowledgeable.

Regarding quilt sizes: always read what the quilt size is before you start. I have a beautiful quilt UFO that I started thinking it was 12 inch blocks like the sample I had seen in a quilt store, though I was making a twin not a lap. I was sewing away and thought something was wrong. Found out the blocks were 16 inches and the twin was the same length as the King. Well, the whole quilt looked awful ! Now I have to take the border off and redo the quilt into two different quilts. This pattern was by a very famous quilter, someone just goofed (IMHO).

There is one store that's a bit of a ways from us that's always been a bit better. I just have to "plan" to go there, because it seems to slip my mind every time we're in the city. Certainly not their fault for sure. ;)

This is a good point. Luckily, I mocked this one up in EQ first, so I definitely knew what size blocks I was making, but I can see how 1/3 bigger would really influence the size look and shape of the quilt. Sorry you had that experience!