Question
My daughters wedding is fast approaching and I need to make sure the dendrobium orchids will fit in the top of 24 inch tower vases with little over 1 inch opening.  she does not want to use the foam arrangement holders that fit at the top.  She wants to see the stems in the vases. With water of course.  8 to 10 orchids in each vase is what we are thinking. Will that be enough to make a full looking arrangement.  Thank you.

Answer
Yes, 8 to 10 will be a nice arrangement.  You say you are looking at dendrobians... I would suggest you take a look at what the wholesalers/florists call 'arachnids' too.... great flowing look to them and almost any color you need.

To keep the stems from all collecting together, you can make a "string" of plastic wrap or cellophane and weave in and out of the stems to hold them apart.  This will ensure the fullness you want.