1 hr. doing the line of holes that needed upsizing.

Checking my sealant.  Looks good...

... but...  Still a leak in the back which was a bit harder to get to...  Will let the tank empty overnight and put on another layer tomorrow.  Even with this leak it's way better than it was.

Now to deal with this.  As you go further back the holes were more and more off.

One of the more forward holes...

...and one of the more rearward holes.

Time to upsize.  The thing is I didn't want the reamer to just force the holes to align because that would cause the skin(s) to buckle.  Not what we want...  So I started reaming at the forward holes, while holding the skin down tightly and putting downward pressure on the reamer to try and only ream the inner skin down to where the outer skin was.

If I was still seeing the crescent in the in-between holes (ones not reamed yet) that means I was succeeding because I was keeping the proper alignment.  Went all the way down and it went well reaming all the holes.

Deburred the holes and cleaned out between the skins (lots of debris).  Time to rivet with the 4mm rivets.  Making sure to have the right size riveter head (the one on there is too big).

And it's done.  Perfecto!!  No bulges!  I found some more countersunk rivets so I'll do more of those tomorrow.