But I think your chalk idea wouldn't work for the same reason you don't like just putting twice and taking a 6. You're not really getting a score and there is no "closure," if you will. Hmm, did that last one graze the inside edge of the chalk, or the outside? Would it have fallen if there were a cup there? I don't know.
Well sure, but those are rules you'd have to establish with your partner/group at the outset. Does it count if its on the line or does it have to be fully inside? Also, unless you're playing for money, your score is really what your conscience says it is. If you're satisfied with it being on the line, take it. If not, putt again. I'm just trying to find a way to allow these variables for different levels of playing ability without tearing up the golf course or the need to create special golf courses.