I ended up using the James kit I have, as it has a steel coated gasket just like the HD one for the lower rocker box. The upper O-rings are red in color and lack nubs along their length, but aside from that appear similar and fit well.
I had not rotated the engine enough to remove the exhaust pushrod, but was able to remove the intake one. Reassembling the lower rocker box onto the head after cleanup, I'm seeing that the exhaust pushrod has pressure on it that keeps the other end in contact with the exhaust valve tip, but I'm not seeing this with the intake pushrod. It's far enough down that I'm still able to move the intake rocker arm around significantly. Do I need to be concerned here? I've rotated the crank to ensure that the valves are at their lowest positions, but it seems like I'm not doing something right if the intake valve tip has that much slack in it.
Cheers!