What do people mean when they’re looking for double blown pieces? Whish is is beneficial?

Like triple blown this is a very loose term.  In reality, it takes about 2-6 times to meltdown and blow out a piece of glass.  The thicker the inside glass, the more it needs to condense and expand to get the glass all even.  To know if a piece is good, look inside.  If it is smooth, the blower melted the color in properly.  If there are bumps, the blower needs to put in more work.

can you take too much CBD?

Like anything, you can take too much.  But it is hard to take so much as to hurt you.  In large amounts, it can cause drowsiness and other discomforts

Have we ever made a SSV or DBV wand with a built in glass screen?

Yes, it can be done.   Some people like it, but the holes still have to be large on a glass screen, so more herb gets by.

You can see something like this https://www.elev8glassgallery.com/all-glass-female-conical-flavor-disc-and-elev8r-wand-custom/

This can also be made with the spherical flavor disc bowl

Is glass with crushed opal cost for than dichroic glass?

Curshed opal glass can cost more than dichroic glass for the fact that synthetic opal does cost a bit.   Then the blower has to do a bit more work to encase the opal than they do with dichro.  Really it comes down to time, and both that a lot of time to produce the prep.

Can lower quality glass degrade over time even if not used?

The short answer to this is no.  Glass is glass and takes over a few million years to degrade.  If glass is cracked or something seems it is degrading, this is probably from 1 of 2 causes.

First, it may not have been annealed properly.

Second, it could be that the colors were not compatible and over time it cracked.