In many cases, but not all, you may need a new 1" pedestal guard to clear the compass. Many OEM 1" guards are simply too short. Edson has stopped producing 1" straight guards, perhaps in order to sell more top plates and new feet. Certainly a nice sale $$$$$ wise for them. This design allows you to retain the top plate and original feet.
NOTE: Some pedestals do not use the Edson 9.5" hole centers. Be sure you have an Edson with 9.5" hole centers before ordering a 1" SG10 guard.
The biggest problem with any of these upgrades is that many pedestals have the assembly bolts frozen into the pedestal. More than one owner has totally destroyed a steering pedestal by snapping off a SS bolt in the aluminum pedestal. This design does not require you to remove the pedestal guard top-plate and replace it.
For mocking it up in my shop I simply clamp the pedestal guard to my table saw, as shown, but a work bench will work too. This makes setting your height, installing the collars and mounting the plotter yoke to the mounting plate quite easy.
While Edson dropped the 1" straight pedestal guard NavPod makes a beautiful 1" X 58" tall straight pedestal guard, PN# SG10. This guard is tall enough to cut it to the exact height YOU prefer. The SG10 is beautifully polished and reasonably priced.
NavPod SG10 1" Straight Pedestal Guard (LINK)
This SG10 link is to Defender but you may find it elsewhere too..