Distance between hulls etc of power multihulls

[huibes]

Hi, I'm thinking of building a short 4 meter power multihull. For enough buoyancy many cats get too wide for good properties at lower speeds (4-12 knts). Going to three or even four hulls can keep the width down, but how far do hulls have to be apart to not effect each other negatively too much?

Another idea for it is making 5 cm wide strips on each ama from bow to stern that go as deep as the deepest point of the outboard. This would be for flat beaching and prop protection, give some extra buoyancy so the amas itself can be less wide and good tracking while towing. I understand the large wet surface will improve drag, but that can't be as much as a planing 4 meter monohull at well above hull speed? Or am I way off?
Also, will the deep strips on each side of the prop affect prop water a lot?

Any info would be greatly appreciated!