Here is a clickable thumbnail from that first thread. Notice the pencil line 3/32" to the right of the center joint of the mold. I'm wondering if that is the real centerline for the tailblock. After I fabricated some spreaders and got the sides snug in the mold, the end joint doesn't overlap anymore and it actually lines up with that pencil line. I have to cut the ends at the neck block, so I need to take my best shot at determining the real centerline before gluing the blocks in place.
The next issue is with the tail block and neck block. I have Bill Cory's Martin kit manual. It says:
The neck block should not be cut down at all. The tail
block will probably be too tall; it might be marked with a
line for cutting: Ignore the factory mark. TIP: Never take it
for granted that a factory marked line is correct; measure
the height of the rim at the tail and cut the tail block to that
height, plus about 1/16” — providing for 1/32 above and
1/32 below the rim.
My situation is the exact opposite. The tail block is 3/32" shorter than the height of the sides at the end joint. The neck block is 3/32" longer than the sides at the neck joint. The neck block has a pencil line 3/32" up from its bottom edge.
I know how to handle the neck block: cut it off at the line. But what to do with the too-short tail block? I believe it needs to be radiused to fit snug against the top and back. Do I need to replace it?