Back on topic:
You don't have much hardware to work with i.e. shoe, ride plate, loader.I will try to make some recommendations that aren't cost prohibited. Getting every last MPH out of your combination is an exercise in attention to detail.
It doesn't matter what brand or model pump you have, if it is starved for water, thrust is down. Feeding the pump really begins with the installation of the intake. Sometimes the intake is set so bad that the only way to fix it is to reset it. Resetting your Jacuzzi is counterproductive to your plans for the boat and time constraints of the season.
I am not the Jacuzzi master, all of my pictures are of Berkeley style intakes. The concept will be the same.
Pumps get the majority of water from the keel. Shoes and loaders help to even the velocity of flow across the entire intake opening.
You want a nice smooth transition between the fiberglass keel and the aluminum intake. You want to match the elliptical radius of the intake with that transition. You do not want the transition to dive away too quickly or the flow will detach from the surface. You also don't want to carry the radius too far forward.
On a Berkeley style intake, blend the opening approximately 8" to 9" from the front edge of the rock grate recession. Too short and the water will separate. Too far and the pump won't load as hard as it could. I don't know what that corresponds to on a Jacuzzi, but it will give you an idea.
You are not trying to change the shape of the hull, just blend it in. Be careful that you don't sand all the way through the glass right in front of the intake. Lastly, fill any exposed screw heads.
We use Bondo Glass for moderate filling. Regular body filler is fine for small imperfections. Preparation is key to adhesion. Primed with an 80 grit scuffed finish is most desirable.
Remove any gouges and imperfections from the intake fins. These will cause cavitation and lower the impeller inlet eye pressure, reducing thrust. I use a 4" grinder with a 36 grit flapper sanding disk and a rough cut file.