You need to talk to a prop expert, they should be able to straiten you out. Check your drive height. The relationship of the botom of the boat to the propshaft centerline. Get the outdrive as level as possible, take a strait edge and run it from the bottom of the boat and extend it to the outdrive. Measure the distance. This will be good info to have when you try diffent props.

If the drive is 1.5, and its a 24 Bravo ie 23, 4500 rpm and 68 mph = -5% slip

I thought that Velocity hulls had a significant sized pad on them which should make them less susceptible to chine walking. They are built for speed as the primary goal. Severe chine walking with a 26' Velocity at 68 mph sounds wrong. First you should check the tightness/condition of your steering system. Is it hydraulic? If you are using excessive drive trim to raise the bow to increase speed that can incite severe chime walking as well. If you are not running at rated motor rpm your prop has too much pitch. You can buy a smaller pitch prop or have the current prop labbed and request a specific increase in rpm to run at the motors rating. Just my 02.

The boat has an external hydraulic cylinder for the steering.when they put that on does it become the primary source for stearing or does it just assist?I am new to boating and am just trying to understand exactly what everything does and why it does it, i run this boat in the atlantic off the coats of ft.lauderdale. and this was a lake boat so im sure it needs a few adjustments to get the most out of it for these different conditions

It becomes the primary source for steering but the condition of the drive gimbal is also important as is the condition/tightness of the steering gear and control cable to the hydraulic steering valve control assemblyassuming that this is not a full hydraulic steering system.

What kind of water conditions do you run in where the "severe chine walking" occurs? I was assuming you were running lake/river water not ocean in a 26' boat.

I would say 2 to 3 foot seas, i can get about less than 1/16 inch play on the outdrive when on the trailer when i push it back and forth.