RSVP on Save the Dates

ccinspire13

My fiance and I are planning two events, one in Ireland where I am originally from and one in the USA where he is from. I have estimated numbers for each event but given the requirement to travel I have no idea if I have gotten it right e.g. I am finding that some people I would have thought would find it more to convenient to come to the US are happy for the excuse to visit Ireland. I would like to get some more accurate numbers so we can do more accurate plannig. Our Wedding is planned for September.
Is it acceptable to put both dates on the save the date and ask people to rsvp if they think they will attend one, other, both or none?

Avion22

People don't RSVP to save-the-dates.   And even people who tell you they can't make it should still be sent a formal invitation in case their plans change.

Since you're dealing with international travel, I think it would be okay to send your save-the-dates 9 months out, and invitations maybe 10-12 weeks out (international mail can take up to 2 weeks).    You can have international guests RSVP via phone or email instead of sending back an RSVP card.