I picked up one of these new ARMS #19 LD mounts from Ned at MSP... I have a TA31 with a ARMS #19S on one of my M4's. This gun also has a #58mod SIR on it. The ACOG sits a little high on top of the SIR. I've used this gun in this way for a long time. Its got to be coming up 4 years now. It's been a great gun for me, very accurate and even though it is somewhat heavy, its pretty well balanced. I've used this rifle in numerous classes, and competitions. While the added height of the ACOG has never bothered me, I would have liked to have had a lower mount.
This new lower, dual throw lever mount sits noticably lower than my ARMS #19s or LaRue ACOG mount (mine is an older model, not the newer low one). Like an idiot, I failed to compare this mount with Trijicon's standard TA51 thumb screw mount. The TA51 mount is the lowest one I was familiar with. Tomorrow at work I'll compare those two to see which is lower.
This new mount still doesnt put the ACOG as low as it would be if it were mounted direct to the flat top, but it does help.
ARMS #19s on right, #19LD on left
closer shot
Older LaRue mount on left, ARMS #19LD on right
I'll get some better pics and a comparison with the TA51 tomorrow.