If your Pilot is MY 2006 or newer, and your Radian has SuperLatch, I'd just wait until he's consistently over 40 lbs. Then I'd remove Safe Stop and switch to a seat belt install at the same time.
Anyway, that's what *I* would probably do. Really I think it's a judgment call. Honda tells owners that they can use LATCH up to the limits on the car seat, but they tell the writers of the LATCH manual to discontinue use at 40 lbs. I'd go with the more conservative recommendation but I'm not going to stress about whether my 39.4 lb child might be 40.1 lbs tomorrow when he's got heavier shoes on and just drank a glass of water.