I use molded cups too. Recently I realised that if you use a regular bra, it often look disproportional small compared to costume bra's from of the rack costumes. So now I use cups that are one size bigger or I add more coverage to the upper edge instead of cutting away material for a shaped edge.
I reinforce my cups with floral wire around the edge, and fusible interfacing on the cups. Then add outer layer of fabric, throw it into a big can with 1/3 beads and 2/3 sequins, maybe add a swarovski crystal for extra bling and finish off with fringe. Don't forget to stir.
Don't be afraid of making your own costume! It's so much fun!