F-704H "Pre-Riveting"

I'm at the top of page 8-10 in the build manual, taking care of the "laundry list" of items that have to be done before final riveting of the F-770 side skins onto the fuselage.

The instructions have you rivet the top five rivets attaching the F-704H center section side plate to the skin forward of the spar cutout (see photo below), leaving the bottom one open until the skin goes on. They have you rivet all six holes aft of the spar cutout. Drawing 28 calls out -5 length rivets for the top five holes and -6 length for bottom holes forward and aft of the cut out.

My questions:

1) What else gets attached here that would require the longer rivets?

2)How would you buck that forward rivet after the skin is on (due to interference from the center section spar)??

The forward bottom skin goes there. The plans show a LP4-3 rivet in the front bottom hole.
Drawing 28, forward side skin F-770.

Thanks Arnie, it now makes sense! I was misinterpreting the star symbol in those two bottom holes on drawing 28. I thought they were AN470-4-6 (8-pointed star), when they are actually LP4-3 (6-pointed star). It looks like the aft bottom hole can take an AN470-4-5, like the rest of that line of rivets?

Although the drawing shows a LP4 rivet in the aft hole I installed a 470 like the others above it.