My thinking is that he may have a much better swallowing response if he killed the prey and was in feeding mode instead of a prey item just being shoved into his mouth. I think it's at least worth a try. I wouldn't give up on him eating naturally after only one attempt. Either way, good luck with him.
Do you have a pic from the side that shows the upper kink? It seems almost impossible to me that he could not swallow a day old mouse pink if he really wanted to. I just hatched out a 30 gram snake that was eating mouse hoppers as it first meal. I know yours has some special circumstances, but I think if the pinky pump can get down his throat a day old pink should be able to as well.