You definitely want a tripod positioned up wind with a checkered flag or marker on the opposite downwind side. Use the tripod and the checkered flag for intersections and try not to move with the wind changes. You do want to see the maneuvers, otherwise what is the point?
Like previously said, practicing to one side or the other of dead downwind is not necessarily a bad thing if the wind changes a bit. It will happen at a contest with the added benefit of also changing for overhead maneuvers. Use a bit of common sense here, biasing maneuvers around a changing wind is fine with 7mph winds, but it is an entirely different animal in 17MPH winds. Some days are just not good filming days.
For focusing, most video cameras and phones have an AE Focus Lock. Focus on the downwind checkered flag and use AE Focus Lock with a higher aperture (11-16 is OK - even F8 will work in a pinch) and the fastest shutter speed you can get with those aperture settings for the lighting conditions. Your focus will not change once you enter AE Focus Lock. Bright daylight will yield the best combination for aperture and shutter speed settings.
If you are using a phone camera, do NOT use the digital zoom feature in your filming. It will result in much lower image resolution. Even optical zooms lens are not ideal. Use your feet and a non zoom lens of the correct size to position the tripod, just make sure you can get most of the pattern in the view without getting too close to the inside of the circle. You can get a variety of clip on wide angle lenses for most phone cameras online (Amazon, etc.) which will fit the bill with a little experimenting. My iPhone XS has two separate camera lenses, one wide angle and one telephoto. You can experiment attaching a wide angle clip to either of the cameras to add more flexibility to the equation. With phone cameras, never activate the digital zoom by pinching or pulling the screen.
Get your camera up high on the tripod - five feet if you can get there or the closest you can get to that. Shooting from a low or high angle distorts the image (and the accuracy of your maneuvers on film). You might consider weighting the base of your tripod on windy days to keep things steady. Some cameras have image stabilization, thought I have not experimented with that. The bottom of the frame should be no lower than the feet of the pilot. I personally try to get the pilot waist up to include everything I can of the maneuvers.
Along with the other benefits of using a tripod, if you have a helper who can actually operate the tripod while you are flying, they can use the tilting feature to raise the camera angle for overheads if needed. Panning is not much of an option considering your helper may have no idea when or where you are going to start a maneuver if you decide you need to follow the wind. Light winds are obviously best for maintaining the same intersection points consistently thru the flight.
You have a lot of good suggestions here - good filming