How to fix the battens though? I want to avoid making holes in the cladding. Maybe masking tape and super glue could work, although it could be disastrous if it failed mid cut.
yeah, you want to make sure it's fixed securely.
Maybe leave the two end pieces of cladding off to give you somewhere to fix the guide Then mark and cut the last pieces by hand off the wall.
hmm, thinking about it, it would probably flex too much over any real length
just temp fix a batten (or 2) horizontally along the bottom, and use that as a saw guide?