Question
For a rehearsal dinner I am making a grouping.  One cylinder with floral sprig or one flower and floating candle.  One small arrangement and one bowl of candy.  Please advise heights and floral suggestions.  Would like to include yellow and keep cost down.  (was considering orchids or gerbers??) I want it simple and modern but not Asian. All square or round containers, or varied?  Event is in May in Philadelphia. THANK YOU!!

Answer
Groupings are a nice way to do something a little different. Since you are looking for simple and modern, I would suggest keeping the shape uniform. Cylinders are generally less expensive than squares and come in many widths and heights. If you prefer squares, you could use a mix of squares and rectangles to achieve the right grouping. The heights should be staggered, and should look balanced as a group.  The heights can be whatever you are comfortable with.  If the room is stark with a high ceiling,and you need some punch, go tall.  If you want something more intimate for the guests while they're eating, you could have your tallest vase at 12", and down in size from there.
The visually heaviest element (probably the candy) should go in the lowest container.
I would either do a floating candle OR a flower(gerberas float well) in your 2nd shortest vase, and maybe 1 gerbera in the other vases(at varying heights) You could also do 1 yellow tulip in the tallest vase, and 2 in the next size and 3 in the lowest. Your flower choice depends on the look you're trying to achieve.  Orchids would be nice as well, but will always have a more asian feel than most other choices. Gerberas or sunflowers are a youthful, fun look....tulips are springy and a bit more sophisticated looking.
Hope this is helpful, and please let me know if I can help further.
Peggy