Uniform number for WR/C?

[MECU]

I have a player that wants to play WR but I want him to play C which he is willing to do. I've got another C so I can play the backup and reward the kid by playing WR.

However, I'm concerned with the jersey number. I can't give him a standard OL (50-79) number because he will be ineligible when he lines up at WR. But is it okay for him to have a WR number (81) and then lineup at C, which by position of lining up he is then ineligible? Is there any other rule I'm forgetting with this, like I have to have 5 OL #'s out there? Should I remind the officials before the game that I understand he's ineligible at that position since this is fairly unique?

NFHS rules. Thanks for your help.