I would recommend getting a kit that includes a 28 nd filter. you'll need it on bright days, and most kits only go up to 14 which hits it limit on overcast days. Your shutter speed should be roughly twice your frame rate. Best results by far are shooting in manual mode, just like with true photography. Once you get used to it, you will quickly hit a few buttons and get it set. It's not a hassle, it's you bonding and taking full advantage of your machine. I'm also not a big fan of polarized filters. They are fiddly to get adjusted right, and have a very narrow effective angle. If you shoot a lot of video over water, it can be useful, otherwise I'd recommend getting just regular quality ND filters. Also, I'd carefully read the reviews. Many cheaper ones are too heavy, cause gimbal calibration issues, and can be really hard to remove. I had a cheaper set that was very heard to remove, and I always worried about breaking the gimbal, even though I had a tight grip on the barrel as I tried to take it off. Polar Pro is good, but they tend to include polarized filters, and if they aren't adjusted perfectly, they can make cloud and sunset video look less appealing. Davinci Resolve is a great free program that will serve you well. You tube videos will help you get up to speed, and I think you will really enjoy just how nice you can make your video's look. If you've seen some of the MP video's uploaded here, you know just how spectacular the video quality can be. In the end, I think you will come to appreciate your MP more and more.
Regards,
Kevin