As for the try I think when it is a short fieldgoal or on the try after TD the U should go under the post. The major problem, like you pointed out is no LJ on the fake can be a big problem. I think then on long tries the R should cover one post and just have the BJ under a post. This method really depends on the distance of the attemp and you need to be clear on what your crew will consider long or short.

I checked the CCA 5 man book.
 

I checked the CCA 5 man book and found some interesting things in the illustrations.

(By the way, the CCA 5 man book is a good reference to use for reading the keys that the BJ, LJ and HL have to focus on and communicate with each other.)

On kick tries and short field goal attempts the LJ and the BJ are behind their respective uprights. The Umpire is shown near the goal-line. This may be a good position because the HL and the U can cover the goal-line (in a 7 man crew the SJ will be placed on the goal-line during a field goal attempt unless he is used as a double umpire) and the LJ and BJ can get back to cover their respective side-lines.

On punts the BJ is shown on the same yard-line as the kick receiver, but near the sideline on the HL's side. Then the LJ will come down his sideline on the snap. If the punt goes out of bounds on the fly on the LJ's side then the R will point to the spot, and the LJ will go past that spot, turn around and then come back until the R signals him to stop.

In a 5 man crew the LJ and the BJ will do a lot of running to be sure.

We use these signals.
 

When the R sees the kicking team coming out with the tee he will touch his fingertips of both hands over his head. The U will pick up and repeat this signal to the LJ and BJ and then they get into position behind their uprights.

If the kicking team is going for it on 4th down and/or no tee is on the field for the try, then the R and U will make the rolling fists signal above their heads alerting the LJ and BJ to take their normal scrimmage play positions.

I am new to this particular board, so forgive me for adding my two cents so soon.
In our state we keep the punt coverage close to the mechanics for a number of reasons. First the Umpire needs to cover interior line play because action on the snapper is a very important thing to watch, and I don't think he can truly see it well from any other position. Second, he needs to be in a position to see the second wave get downfield as the L and LJ have the gunners and the rest of the first wave. Third, the U and R will be in excellent position at the sidelines for OOB coverage on the return, or to cover the Goalline in case of a breakout.
On tries and FG in case of fire the U can step to the goal line and in the event the play goes to the LJ side, can box the play with the R. We feel that those plays constitute a very small percentage of kick scoring plays so we are willing to take the risk of not having the LJ on the LOS.

Would be something to try??
 

Maybe in Pre Season Games and Scrimmages,
and see what happens.
What do think Bob F.?
Harry D

REPLY: snake-eyes...we used the technique with the U under the post for about two seasons until our state association told us to "cease and desist." They felt that positioning the U under the post could compromise the protection offered to the snapper. We don't necessarily agree, but that's what we've been told. And, since going to five men, we've never experimented with the R calling one of the uprights. Because of the distance away, I would think he'd have a tough time on close ones determining whether the ball was inside or outside the upright at the moment it passed over the crossbar. So we go "traditional" with the L and B under the uprights, and scramble like heck when there's a fake or a busted play to the L's sideline.

That's no good about the U being under the post, I do agree about the R calling kicks above the uprights though, it's really a tough call.

The positioning our association has adopted for FG's and PAT's was taken from an article in NFHS quarterly I believe. In a 5-man crew the BJ will be under the goal post as will either the HL or LJ depending on the whether the kicker is right- or left-footed. The R will always be about 8 yards to the side of the holder and looking at the holders chest. Whichever wing is on that side will be under the goalpost with the BJ. U will be at his normal scrimmage position. If there is a fake or busted play, the R is in good position to get to the vacant sideline and the other wing is still "at home" to cover his normal sideline. If the fake goes to the R's sideline he will trail the play as it goes upfield and the wingman under the goal will get to the sideline and then head upfield towards the play and hopefully get to the goal line before the runner. So far it has worked pretty well. We generally try to notice which foot the kicker is using during pre-game warmups.