You can use the Compass Caddy with your existing equipment. It fits most compasses and most walking/trekking poles.
Fits most Compasses
The Caddy is designed to fit most commonly used orienteering or baseplate compasses. It is a one-size-fits-all design, and can accept compasses with baseplate widths varying from 49 mm (1.9") to 61 mm (2.4"), as shown below. This covers the vast majority of compasses.
By offsetting narrower compasses to one side of the Caddy (middle image above), the long edge of the compass baseplate is in contact with the sidewall of the Caddy, which in turn keeps the compass parallel to the shaft of the pole. This is important when using the pole as a pointer, for example when taking a bearing.
The circular cut-outs in the wings that hold the compass are designed to be a close fit to the compass capsule in that scenario, ensuring a snug fit.
The length of the compass baseplate is relatively unimportant with respect to fitting the Caddy - unless it is very short, in which case there is not enough length of baseplate for the Caddy to grip. There are few compass models that fit that description.
Fits most Trekking Poles
The caddy is designed to fit any walking or trekking pole with a circular cross-section, and a diameter of 18mm. This is the de facto standard size for the majority of poles.
Some trekking poles have a narrower top tube of 16mm diameter. By wrapping a few turns of tape around the pole, the Caddy can be made to fit these poles. Some other poles have an oval cross-section, which is not compatible with the Compass Caddy.