I think a lot of it depends upon your tow bar type and its physical condition. With my first Roadmaster Sterling All Terrain tow bar that I purchased used off of eBay, I use to have a real hard time getting it to release from the car. After a few years, I traded it in on a new Sterling AT and this thing comes loose from almost any angle without any trouble at all. I do keep it lubricated with silicone spray as I also do with all the pins and moving parts.
I always put the car in Park and then pull the cables and keeper pins. i then pull up on the release levers and pull the pins out. If the large pins are stuck, I can pull the trans back out of Park and let the car move an inch or so and that will usually free up the pin.
However, I agree with the others.... keeping the car in line with the mh will provide you with the best disconnect position.
Ron