My full and long battens are removable. I keep/store the battens
inside the boom when not in use (also keep two spares there).

Full battens (and short battens too for that matter) should be
adjustable to effect proper sail shape. This is easily accomplished by
using velcro on the inside of the batten pocket and a velcro on dacron
'tab' that you push inside the batten pocket alongside the batten, the
only thing that sticks out is a 'retrieval tape' that is used to
extract/remove the velcro 'tab'. You use a 'batten' pusher (short
length of batten) to adjust the batten tension by how hard you push the
velcro 'tab' into the batten pocket.
For expected very high and very low wind ranges a flat enty sail (for
'speed' sailing and the avoidance of flow separation) can be easily
accomplished by using minimal tension on the batten. For 'powered-up'
(rounded luff entry) for drining into chop or oncoming waves, etc. I
use lots of batten compression. ..... all easily accomplished by how
you 'load-up' the battens!!!! Until now the usage of velcro to
affect batten tension was externally applied to the batten pocket and
the velcro quickly degraded in sunlight and weather exposure. Putting
the velcro on the inside of the pocket results in much longer service
life.
If you cant adjust the batten tension you cant help to change the sail
shape, especialy in the 'middle' of the sail where the effect of
halyard and outhaul, etc;. control is minimal.