does it continue to react with the I2 for as long as it reappears in the reaction, or is there some problem with doing this?
Although, swim is far from an expert on this, in his reactions when he has used too much RP, this seems to be exactly what happens.
As far as swim knows excess RP, doesn't hurt a reaction. (Swim is talking a few grams) In fact swim likes to use what most would consider excess MBRP, if it has been run before. If it is it's first run, though one can cut back to .60RP:1 E.
As Geez and Jacked both pointed out the ratio of RP should be in relation to the I2 rather than E.