Hi,
The alignment of tail halves and the importance there-of was mentioned recently in an other thread and quite correctly.
Back in the day,when we were producing our OD stuff we came up with the following to deal with this ;
We made the tail halves as if they were for a one piece tail, going through the fuz,, .
We then joined/glued them having jigged them up for perfect alignment (as close as possible anyway).
Then the outer tubes are dropped in from the top (or bottom) having been boxed in balsa first.
The tubes/boxes are put parallel to each other in plan and end views. This assure ease of assembly there-afterwards.
Then cut the halves apart again (two cuts), face with a root rib and discard the middle piece. Rejoin with inner tubes for that 'perfect' alignment !
Finish the boxes to profile and they are ready for covering - a 15g glass patch over the top is a good idea, but not required, if using film.

The adjustable tube is run through a box in a box and shims are used to adjust. This is stiff and not subject to loosening up or pivoting even if using a YS.
The foam former is plenty stiff enough and is not subject to popping loose if jarred. It and the boxes weigh 9.5g. The equivalent in a factory job (the screw in the fuz,, type) weighs between 20g and 30g not including the tubes.

Brian