Badly rusted, worn, or damaged wheels with a removable bead ring can be just as deadly as a RH-5, especially if one is a bit careless when assembling them. If the wheels you're using have tapered lug nuts with a corresponding bevel in the wheel, oblong holes are a definite problem. If the lug nuts fit flat against the wheel with a built-in thrust washer, a slightly elongated hole isn't as serious, but they need to be checked for tightness frequently. Elongated holes on a drive axle will be more of a problem, as the torque load of accelerating and braking will let the lug bolts move back and forth no matter how much the nuts are tightened. If you have a choice, put the better-condition wheels on the drive axle(s).
Jerry