Twanda
Great observation working with the front knee. For your situation there is no limit to how much you can flare the front foot to support your motion. The only thing to watch is to make sure the back foot stays slightly flared out as well (no more than 10 degrees is needed) and make sure you are able to perform all of the backswing movements with full range of motion, no limited by the front foot being flared out.
The more the front foot is flared out the more this should help ease unneeded stress. You may notice, as you perform some of the body movements, snap the knees, surf to level and thrust through impact, these will be much easier to accomplish with the front foot turned out slightly more like you are talking about.
The good thing about the Tathata Golf motion is that the front knee isn’t rapidly straightening or violently snapping straight through impact. That being said, I would imagine you have found one of the best movement patterns to learn to ease any unneeded stress on your knees.
Hope this helps, happy training!