How do I use Chicago Style with British, Australian, Canadian, or other spelling preferences?

The preferences in The Chicago Manual of Style for PerfectIt cover a wide variety of PerfectIt’s checks. However, most of the regional-specific spelling is in the Spelling Variations check. The easiest way to enforce all of the preferences of Chicago Style without those is simply to turn off the Spelling Variations check using the Choose Checks drop-down. Here’s how: