Follow-up spacing
Three messages, then stop. Chasing past three annoys people and costs you the referral later.
Message 1 — the opener
Day 0. Short, specific to their site, one small ask.
Message 2 — the nudge
4 working days later. One proof point, smaller ask.
Message 3 — closing the file
A further 9 working days. Give them an easy out. Then leave them alone for six months.