Seedlings are often planted in community pots (compots). Breeders, and the rest of use with limited space, allow those seedlings to grow to maturity and flower in the compots. At that point, the breeder would select out the best.
Kerry's Orchids of Florida supplies many big box stores and other east coast outlets. They pot their Phal seedlings in four in pots for retail. To achieve a six inch pot, they combine two four inch plants.
Kerry's
I think your idea will work fine.
Charlie