Can I please make a suggestion to improve this awesome addon.
Assuming I've chosen to send reminders after 30 days of inactivity for upto 120 days in the options panel.
Can the cron run daily, and each day send only to members inactive for exactly 30, 60, 90 and 120 days. Rather than doing a large batch once a month?
This avoids having a large batch of emails going out each month, spreads the server load and ensures members get a reminder to come back on their 30 days anniversary, rather than up to 2 months later if they joined just after the day the cron runs.
It should be quite simple to implement this, and will address many questions or reservations people have already posted on here.