Submerged arrangements like this can be stunning and cost effective. We could do a mixture of something like this, only as you suggested, with more vases (I think 5) on each table, for half of the tables, then fuller low centerpieces for the other half. And candlelight all around! Also, these could be repurposed to line the aisle during the ceremony.
Pretty center piece idea :) this is my color! Hand painted teal orchids used in both Ceremony and in reception. Long multi stems work best in these vases. Rent in the Savannah/ Hilton Head area for $25.00 for all 3 vases. *** THESE ARE SILKS**** SAVANNAH EVENT DECOR