Yes to dimples whenever possible. That's what can be a bit frustrating with today's slightly narrower tie widths (ie. not getting a good dimple out of an otherwise great tie). Not always a problem though, thank goodness.
Freckles on girls are as attractive as getting splashback on your pants. Dimples are nice for wider woven ties, no dimples for skinny ones and any old random scrunching is fine with knits and raw silk or woollen ones.