I have received the 6" x 2" plate RAM-B-111B, thanks Steve!
I just did a test setup like this:
The plate is mounted to my speedo mount with a short RAM arm. The RAM bracket for the StreetPilot 2610is bolted with its back to the plate. On the other edge of the plate, I have mounted a 1" RAM ball and the yellow GPS60 is on a RAM mount with standard length from there. So the 2610 is almost in the same position as where I have it normally, the GPS60 sticks forward quite a bit.
It is quite possible space-wise, but the lever from the dash to the yellow GPS60 is huge.
I went for a little ride with this setup. On a good surface road and on the motorway the movement is a bit more than what I'm used to but it is acceptable.
On a bumpy paved road the wobbling is too much. Especially the yellow GPS60 moves about A LOT. The movement of the 2610 is more than otherwise but not really bad. So I think the most important factor is the lever length. Second factor is the total weight.
I would NOT want to ride with this setup. But then why would I want two GPS units in the first place? I'm pretty sure it is usable with lighter units mounted ON the plate, without an extra lever. For example a Quest and an iPod, a mobile phone, etc.
What's the size and weight of that Road Angel thingy?
If I have the dimensions I can make a dummy and try that next to the 2610 to see what the result is.
Cheers,
Michel