I recommend to not connect the decision abot the BB-project on those gunners you have.
you mentioned those are acc-gunners, so I would advice to forget about this pair of gunners, since rld-gunners are definately to prefer. there are threads in forum which explain the reason why. pls stick to those explanations before executing something blindly.
basically RN is a very good nation for playing BB, especially for beginners.
the dunkerque-guns have an ugly spread and its only getting better if the gunners reach a very high level. for my personal taste even level 110 isnt quite satisfying.
I would prefer Resolution and Valiant to make my way up.