a very good question and a difficult decision to make. what to do about the precocious bloomer?
now some phals will bloom small, i'm thinking equestris and its types. but 4" ls is small. it will take a lot out of a young plant to bloom. a percentage of those will bloom and then sulk and never really recover. not to scare you, but these things happen across a variety of genera. for the long-term health, pinching precocious spikes will be beneficial. the thinking being that you'll get an infinitely better blooming at a later date, and without any risk to the well-being of the plant. but that's easier said than done, since the precocious bloomer may only throw a couple flowers and do fine down the road. but i still think blooming early will set them back in their growth to some extent.