DBAL mounted at 3:00 or 9:00?

Assuming you have a co-aligned version. It is a little more involved when setting zero but it will work without any major issues. Since the lasers are co-aligned, the zero is easy to set, try this on a DBAL-I2 and you will have a harder time getting it set.

I've got a DBAL-D2 on top and while I can see it with a 1-4, when magnified, it goes away and works well. This is with a ADM Recon=X mount which is at 1.47" You might play with it at 12 o'clock and see if it is really a problem. My ATPIAL is at 3:00 with a SF Vampire at 6:00 no issues with dot or LPVO.
 
Thanks for the input. It's the D2, so co-aligned lasers. It'll eventually get a Vampire or similar, so I like the idea of having the DBAL on one side and the light on the other. If I knew it was going to return to zero readily, I'd probably not worry about it and just take it off for day use.