buying plastic for drypoint prints

i have decided to create a set of 6 nonsense prints at this size (21.5cm x25.5cm) 

i decided on this size as i wanted the prints to be big enough to stand out however i thought any bigger would take away from the small detailed effects that can be achieved with dry point process, i also thought creating 6 prints at this size would be viewed better as a whole at this size. 

i feel if they were bigger i feel there would be to much negative space around the etchings.