I had a hard time finding the right wording for the sand ceremony, but this is the one we went with:
"Today, this relationship is symbolized through the pouring of these two individual containers of sand into one, representing you, Michelle, and all that you were, all that you are, and all that you will ever be, and the other representing you, Zachary, and all that you were and all that you are, and all that you will ever be. As these two containers of sand are poured into the third, the individual containers of sand will no longer exist, but will be joined together as one.
Michelle, pour some of your sand which will represent you as an individual."
"Zachary, pour some of your sand which will represent you as an individual."
"Zachary and Michelle, now pour your remaining sand into the container together to represent the joining of your two individual lives into this one union of marriage."
Just as these grains of sand can never be separated and poured again into the individual containers, so will your marriage be."
I believe we kind of changed the wording a bit from some that we found online, and this one seemed to suit us the best. You can always play around with the words and find something that you both really like though. For the rest of the ceremony, we did the same thing you plan on doing, where we kind of cut and pasted a couple of the ceremonies together to come up with the perfect one for us. For when the reading should be. i've seen it a couple of different ways but I saw online that it should be after the "who gives this woman to be wedded to this man". Hope this helps some!! Good luck!