I understand that a flat side creates a tighter wobble than a round profile. What conditions or situation is one better than the other or is it just one of those things you have to feel out?

Generally speaking, people will suggest using a flat side bait with a tight wiggle when the bight is tougher such as cool water or high pressured fish situations. Round profile cranks usually create more disturbance in the water and are recommended for active fish and for low visibility situations.

Like you said, it's still a "feel" thing. We don't know exactly why one works better than another. These are just observations made by others and it provides a guideline to begin with.

Also just because a crank is flat it doesn't mean it will have a tight wiggle and the same holds true for round baits and having a wide wobble.

in cold water ill throw a wide wobble, in pressured or hot water ill thow a tight wobble.  my favorite tight wobble which i throw about 80% of the time is a Spro Little john in either the shallow of deep diver version.

Flat or round has nothing to do with wide or tight action....that is entirely a matter of overall crankbait design (especially lip angle and line-tie orientation).

For that matter...flat cranks with tight action work year-round in any condition. Just like lipless cranks, which are very similar in action and profile.

I have some round cranks with very tight, lively actions, and they're also some of my top producing baits.

Also - flat cranks are capable of producing more vibration/disturbance than round cranks.  Think about it....take a flat object and swing it back and forth under water, then take a round object and swing it (like a flat bat vs round bat)...the results are pretty obvious.   

I understand that a flat side creates a tighter wobble than a round profile. What conditions or situation is one better than the other or is it just one of those things you have to feel out?

I say it's the latter; there are way too many occasions when bass don't conform to our conventional wisdom; we just can't predict with much degree of accuracy what they'll do at any given time.

Also - flat cranks are capable of producing more vibration/disturbance than round cranks. Think about it....take a flat object and swing it back and forth under water, then take a round object and swing it (like a flat bat vs round bat)...the results are pretty obvious.

Never looked at it that way.  Makes perfect sense.

Also - flat cranks are capable of producing more vibration/disturbance than round cranks. Think about it....take a flat object and swing it back and forth under water, then take a round object and swing it (like a flat bat vs round bat)...the results are pretty obvious.

Never looked at it that way. Makes perfect sense.

Yeah, it does to a certain degree. However, the lure is moving back and forth in a fluid motion not being thrashed. If you're fishing it right

Not disagreeing just speculation.