Recently I've given thought to what my bluffing ranges should look like in various spots. One of the distinctions I've been considering is what that characteristics that range has with cards left to come as opposed to not having cards left to come, and more specifically in position.

Consider a simple spot on the river where we are last to act heads-up and we're facing a bet that will put us all-in. Clearly we call with the top of our range (whatever portion is necessary) and fold the rest, so it looks like:

<---fold---|---call--->

So now consider the same case except we're not all-in. Then above our calling range, we have hands that we would raise for value with:

<---fold---|---call---|---raise--->

But if we have a range where we would bluff raise with, it would come from the top portion of our folding range like this:

<---fold---|---bluff raise---|---call---|---value raise--->

Now let's back up a street. Suppose we're on the turn instead, and again someone puts us all-in. Our range looks the same as before:

<---fold---|---call--->

Now if the bet doesn't put us all-in and we don't have a bluffing range, it looks the same as before:

<---fold---|---call---|---raise--->

But when we add a bluffing range here, I run into a problem. Should the bluffing range typically include hands that would be +EV to call, or should that range mostly come from the top end of the folding portion of our range?

I'd like to see what people think about this question before I go any further.