I'm the same height, and having the same issues. I was using feet tucked for a long time. I tried feet wide and flat, felt awkward at first. Like you you said more stability, but less of an arch. It sucks being long legged and using average/low height benches.
However, over the weekend, I watched a TON of Clint Darden's videos. He's our height, and he has about 6 or so videos on the Bench Press, actually just had an article yesterday on it on EliteFTS. Go watch all his videos, THEN give it a try. I gave it another shot Monday with the wide stance, and I got a TON of leg drive, and was able to reinforce my arch with leg drive every rep. I'm not saying it's the best foot placement out there, but I'm going to give it a legitimate shot over the next 3-6 weeks and see if I can get it down.