So this is how I will mod at least 2 of my gunboats.
Remove the top fin and cannons (green circle) and replace it with 1 of the smaller, side wings (red circles).
Remove the smaller side wings, and add a pair of ordnance tubes (blue circles) from another gunboat, or if I find something else suitable. I will go and look at the toy sections.
Then I will file down the large cannons on the main wings, and use the cannon pair removed earlier to place it on the chin.
Then my custom paint job, red tinted windows and a darker grey color, and blue engine glow. Will post pictures about the project when I start.