Bottom line is, do whatever makes it fun for you personally, since that's the only person you have to please, unless your name is @Tunedpipe then your wife's crawler better be what she likes!
Rules, Meh! I don't need rules to have fun with my crawlers, competition doesn't interest me. I do like a challenge but have nothing to prove, but to myself.
I know lots of folks are highly competitive but I'm not one of them. Just enjoy.