You want the ultimate Stargate control panel ?
Check out the Multi-Williams CP, it has 2 8-way joysticks and the button/stick layout for Stargate, it's compatible with all the Williams games (Stagate,Joust 2 player,Robotron, ect) and I estimate the layout is compatible with over 1,000 MAME roms (due to the 8-way sticks)
The Multi-Willaims CPO can be found here (printable) :
http://www.localarcade.com/arcade_art/details.php?image_id=231It's a lovely overlay for Williams fans, and compatible with so many ROMs it's certainly something to consider.
If you don't like that and still want to use the Stargate overlay you can mount a regular joystick in the Stargate CP (with 3 of 4 bolts in place) and use a 1 1/8" hole-saw to drill the reverse button hole, it will take out some of the joystick's base but leaves a functional stick (that mounts with 3 bolts)
(that's what Paige did, he's so cool, to honor him I installed a spinner on James Brown)
I personally used an original 2-way Defender stick on a Stargate CPO, the joystick is super slim, which is how they got the reverse button that close. However the control panel is only compatible with hand-full of MAME roms due to the 2-way (verticle) stick.
Can you dig it ?
Craig