On side kick mechanics (5 man) NFHS
 

Is there any associations that moves the LJ to K's 40 and the Umpire to the 50, making two at the K's 40 and two at the 50? We would have better coverage than the umpire staying at R's 45 and the LJ at the 50. Am I missing something here?

The mechanic you describe is what the book calls for and is the one we use in East Tennessee.

We do that so that we have the "neutral zone" boxed in. If the ball is kicked deep, the U and L move quickly downfield and the LJ and BJ slowly move downfield. We've had to use it once this year and it worked really well.

REPLY: That's what we use in NJ--B and L at K's 40; H and U at R's 40.

Here in San Diego we kinda go our own way for a lot of mechanics.

On KO's we have the BJ at the ball, LJ on the 40 (with K), the HL on the 50 (with R), the Ump on the goal line on the LJ side and the R on the goal line on the HL side. If we go to onside kick, the U moves up to the 50 and the R moves to the middle of the field.

Don't you mean HL and U are at Team-R's free kick line (the 50) for a possible short, aka on-sides kick attempt?

That would match the NF guidelines for a possible short free kick.