Schaeffer's #707 Supreme V-Twin is what I used in my Sporty. '06 XL1200L. Never had any abnormal valvetrain noise, but even watching some YouTube videos on the XR, it seems like they do have a more pronounced noise to them. I personally wouldn't let it bother me. Might have something to do with the cam grind, etc. I also remember reading about the oil coolers not getting all their air out of them when the bike was first prepped for delivery, and once the cooler thermostat opened, the bike was roughly a quart low on oil. Always check oil level hot.
A friend's XL883 has a noticeable valvetrain noise as well, and it's been clackety-clacking along just fine. She has it serviced at the dealer, and probably uses Syn3, based on how much they push it.
I almost (and I do mean almost... I was in the sales office ready to pull the trigger) bought a leftover '10 XR1200, but at the very last second decided not to since it was late in the season, and I figured why buy it then pay to insure and store it for the winter months. Come springtime I himmed and hawed some more about it, and finally decided to go a totally different direction, and bought a used, super low mileage 2003 V-Rod. I couldn't be happier.
It's a shame H-D pulled the plug on the XR1200x... I have a friend that races them professionally and she really likes them. Not as fast as the metric liter bikes, but apples and oranges.
for the best resource on the Sportsters (including the XR and Buell). I learned tons there when I had mine.
Like I said though, I wouldn't let a little valvetrain noise worry me. Just run a good oil and filter, change it regularly, and pay attention to noises that seem to change or get louder. Only then would I get concerned.