Vixen will eventually do moving lights much better, much of the groundwork for this is already done. But for now, you have to do it the hard way. The trick is to set up multiple elements for the different aspects of the movers. One for RGB, set it up just like any other pixel. Then additional elements for the X, Y and Z movement and any other parameters you want to control. If there's any channels you need to be set at fixed values such as a master dimmer, you'll need elements for those as well.
all of the elements except the RGB part will patch straight thru to the appropriate channels. The RGB element will patch thru a color breakdown filter to the color channels. If you need to limit the range or scale values of any of the other channels, you can use a dimming curve filter to do this for you.
Custom value effects can be used for cases where you want to send specific fixed values on control channels.
Custom value effects are not good however for movement operations. for this you need ramping values. You'll want to use the pulse effect. Leave the color alone at the default white, and work with the curve. This will let you ramp the values of each axis from and to whatever values you like. It's generally not necessary to think in terms of 0-255 even though that's what's happening under the hood. The 0-100% curve levels will translate just fine.
We'll eventually have a XYZ movement effect as well as movement breakdown filters to go with it. When this happens, that will make things much easier, but it will also mean you'll need to reconfigure to work with it.
Vixen is a lot different than a pro stage lighting console, but it does have a good deal of live functionality. You can easily tweak your effects live while watching them on the actual lights. It's a bit awkward currently to do this with movers with multiple effects on several elements. But that'll be better when we roll in better movement support. We don't have a way to visualize the moving lights in preview though. So for that, you'll either need a professional visualizer software program, or do it on the live lights in the yard.
That brings up the point that the physical position of the lights has a big effect on how the show looks. You're going to want to set up the lights, leave them there, then do your movement programming. We don't have a way to calibrate all of the effects for inevitable cases such as when you place your fixture 2 degrees rotated from the previous year.