I believe this might be what you are looking for:

http://www.pierplates.com/AP%20900%20to%20PierTopPlate.pdf

I had my 900 pier adapter modified in this way. I'm not sure
whether you have a permanent pier installation, but note that the
countersunk holes for attaching the 900 pier adapter to your pier
top plate will interfere with the tapped holes for mounting the RA
axis to the 900 pier adapter unless you can rotate your pier top
plate away from north by at least 7 degrees.

-Eric

--- In ap-gto@..., "pm57uk" <ast57@...> wrote:

Hi,

This is a long shot but I thought I'd try anyway.

I'm going to be putting the 900 standard pier adapter onto the top

of

my flat-topped pier.

My pier top has some tapped holes to match the pattern of the bolt
holes of the meade wedge (centre hole plus 3 holes 120 deg apart a
few inches out from the centre) which used to sit on my pier.

I was hoping to have the AP pier adapter pre-drilled so I could
fasten it directly to my pier for minimum hassle and was wondering

if

anyone might know the specifications of the bolt hold pattern for

the

meade wedge that I could supply in advance to have holes drilled.

(I guess I could paper trace the bolt pattern on my pier top, but

I

don't want to disasemble the mount that is currently riding on it

if

at all possible for the moment.)

Cheers
Paul McGale