Pondering the logistics of 8 cards per A4 sheet, and the cost of printing a full 160-card deck, decided to look again at the test sheet I'd printed during the week. Then decided to see how big they'd be with 16 cards per sheet by turning it to portrait and then pasting two of the 8 card sheets onto it with relevant scaling.
The result is much better I think - they're a bit smaller than a credit card now, as opposed to just bigger than a packet of cigarettes size. The real boon to this is that I'm using half the amount of paper to get the same number of cards. This means that I won't have to fiddle about with four or five way joint cards when I add the Pacific theatre to the set, and might even be able to squeeze some extras in like Kamikaze, V1s, and a decent amount of ship move and so on.