That weight forward is changing the characteristics of that boat a ton, that tank was located there for a reason. I'd attribute the lean to that. Although she is level at the dock, just a slight amount of weight, aka a single person to one side will make that boat very tender underway with the weight forward. Sounds like your getting on plane, but not exactly acting like the hull should. I do not think anything can fix your problem except using a lot of tab after that mod. Moving a fuel tank or any other large components makes a HUGE difference in how a boat will handle, especially on a smaller boat like that. I do this stuff for a living, hull design, tank locations, picking engine, placing bulkheads and stringers and such on larger sportfish boats so I know the impact that moving something afew feet in a boat can have on overall performence. The only way to fix your problem would be to move the tank, otherwise just live with the tabs. Another option i to add some weight under the port side helm seat to counteract whats causing the list, but that will make things worse when you have multiple crew members. I'd recommend having your crew in the cockpit, not all huddled in the helm area when underway, you have too much weight forward and need some aft for that hull to run properly.
Not sure who moved the tank and made thr mods, but it doesn;t seem like they thought about how it will change the hull. Before ever moving tanks or any major compnents, seek a professional, or at the least call Grady and ask for their input, I'm sure they will frown upon it. they spend thousands of doallars inresearch and engineering to locate compnents in ideal locations for ride and stability. This move effected the stability a ton and some of it could have been predicted before the job was ever done. Grady has a 3-D hull, they have the tank, they can move it using software to where you wish and run it through certain naval architecture programs and see how it runs and what adverse effects it would cause, would have been well worth the money to pay abnd have it checked. Grady may have not done it themselves, but C.Raymond Hunt has those hull models as well and for a fee would have did the work, probably an hour to 2- hours worth of work if you knew the tank location.