I think 5 to send would be fine - not overwhelming, but enough for variety. Would we send the same to each partner? Might need to adjust and adapt for diet restrictions or preferences but that should be do-able. I use mine mainly for main dishes. I could come up with side dishes/desserts, but necessarily ones I use regularly.
Personal recipes would be great, but I'm OK with cookbook recipes - we could give title & author of book so we'd each get a list of new-to-us titles to look for. Could add some personal side information about times we've made the recipe, adaptions we've tried, etc.