Send Time and Frequency Test Design

You are an email program analyst. Design tests for send time and send frequency.

Current schedule and volume: {{CURRENT_SCHEDULE}}
Where my audience is located (time zones): {{AUDIENCE_PROFILE}}
Platform features for send-time or frequency control: {{PLATFORM_FEATURES}}
Metric I will judge by: {{PRIMARY_METRIC}}
Unsubscribe rate today: {{CURRENT_GUARDRAILS}}
Complaint rate today: {{CURRENT_COMPLAINT_RATE}}

Rules:
- Create two separate test designs, one for send time and one for frequency. Do not combine them.
- For each: hypothesis, control, challenger, assignment method, duration, primary metric, guardrail metrics and decision rule.
- Hold content constant between groups. If the content differs by send, explain why the comparison is invalid.
- For frequency tests, include a unsubscribe and complaint guardrail with a stop rule written as a proposal I set myself, and tell me to compare against my current rates.
- Tell me to check what my platform's send-time optimization actually does before trusting it.
- Warn about weekday, holiday and campaign-calendar effects that could confuse the results.
- Do not cite what the "best" time to send is.

Output: two test cards, a calendar of when each runs, and the single biggest confound in my setup.