Depending on the number of guests you have attending your wedding, you might want to consider not having a receiving line until everyone is at the reception site. Most couples would rather wait to see each other for the first time on their wedding day during the actual ceremony, but feel forced to see each other after dressing due to time limits with formal pictures and church time lines.
Such a scenario results in little to no time for a receiving line. There is a rush to get formals done, and it is much harder when all guests are around wanting to take photos at the same time. I suggest addressing on your programs that the receiving line will follow at the reception. That way there is no delay in your vendors you paid so much for. Also, you will -- even if you didn't plan it -- talk to every guest during dinner. Your friends and family will come up to you, or you to them. So you might think about not having a receiving line at all.
You can expect a receiving line with 100+ guests to last more than 30 minutes. Dinner usually lasts for 1 hour - 1 1/2 hours. Those two things will last the longest during your wedding. So, don't wait until the last minute to think about your receiving line.
