I'm in Brackish and have used both Tri-lux Spray and in the Qt can. The spray works best in those hard to reach areas and the Qt can brused on with a foam brush and a very small roller (1" x 4" purchased from WalMart) works the best.
That said, I wasn't happy with last years results. I didn't use the boat much from August on. When I pulled the boat in the fall there were quite a few barnacles when in the past I barely had any.
People on the site have suggested that I change to Petit Hydrocoat which I am strongly considering this year.
My thought would be to lightly sand the entire drive. Spray the hard to reach areas with the Tri-lux and brush on the Petit. Not sure if it is the best plan, so I, like you are looking for suggestions/feedback.....