It will work, but it might not be the best fit for you and your 12" f/5. I use 250x or more with a 10" f/5, including a 3-6 zoom at times for planets. I was just using the zoom at the 6 and 5 settings a few minutes ago for 208x and 250x respectively on Mars, but the seeing was poor so both were too much. A few nights ago it was doing well enough at 250x in mediocre seeing. Haven't had particularly good seeing in the backyard with it recently, wrong time of year for it here at lower elevation, but I do go over 300x on the rare nights that allow it.
The field is going to be narrow even at the 6mm setting for 250x in your scope. I haven't done any mods to my son's Z10 I am using, so hand tracking with it is less precise than I would like. I need to ask my son if he wants me to improve the azimuth.
p.s. If you want a better price than Orion, consider the sponsor of Cloudy Nights, Astronomics. They give a discount to CN members if you make them aware of your username when you order.