I would be very wary of using OSB in leui of Paneline / Panelvent if your looking for a vapour open wall construction, typical diffusion resistance factor (µ) for OSB is around 219 (NorBord), i.e. it is not very 'breathable', and certainly much less breathable than the 1.47MNs/g (35 µ) Paneline / Panelvent claims.
Has anyone came across Magnesium Oxide Sheathing Boards, they are a bit notoriously without BBA but I note that they are being used with hemp crete to create breathing walls, there are a few UK Board supplier (they are all sourcing from china), it probably stacks up not bad on cost with panelvent.
I also noticed that Finnforest were suggesting that they had 'breathable' spruce plywood sheathing called 'Weatherguard' but havent; seen the full test data for this yet. I've bene searching high & low for more cost effective alternatives to paneline and panelvent.
Probably too late for your project Catherine but perhaps worth exploring for future builds.