It looks like we give different weights to Grace. But that aside, let's go back to the basics of this question.
If we are told that we have our salvation in our own hands, that we can reject God or harden our hearts to him or live lives of wantonness...and this is all up to us because we have freewill, how do you reconcile the difference in abilities of say, today's college educated Christians raised in Christian homes with, let's say, the illiterate 9th century peasant in Europe with an IQ of 85?
According to standard theological thinking, both are on their own, presumed to be able to choose wisely or foolishly. That's freewill, and everyone is supposed to have enough of it to choose or not choose Christ.
Forgive any imprecision on my part in this post, two month old and a toddler so my brain may miss something
We might not be giving different weights to grace as much as placing its action at different points.
First, Catholics would agree that free will, in its exercise is compromised in a fallen world. We call what compromises this concupiscence.
But Free will is not something you have more or less of, it is a functional ability. God ensures that each person has enough grace to use it evenly so to speak.
No matter what the time period or person God wills the action of Prevenient Grace. This wills them toward good so they may cooperate or reject. They are then given actual grace to assist in the cooperation. This does not even get into Sanctifying grace. (yes sometimes we over analyze and break things down)
We do not even need to look at things over time periods. I am differet from the person next door, who may need more or less help to properly use the function of free will. But it is not more or less free will, it is more or less actual grace should they cooperate. They have the same capacity for free will. Different circumstance may require more help to exercise it properly should they choose to cooperate.
Here is where a Catholic will make a distinction between types of grace like Sanctifying grace which is the justifying and habitual grace and Actual grace which is a transitory help.
So actual grace is given to each, according to their state and need to urge them to use the function of free will properly.
We define actual grace as:
Temporary supernatural intervention by God to enlighten the mind or strengthen the will to perform supernatural actions that lead to heaven. Actual grace is therefore a transient divine assistance to enable man to obtain, retain, or grow in supernatural grace and the life of God.
So the transitory help of actual grace allows us to exercise the functional free will we have from being made in the Image of God. And we may, cooperate with actual grace or reject it. That rejection or acceptance is a matter of the heart and not the intellect. So it can be accomplished no matter the state or differences between people. Although God may illuminate the intellect as well.
So if by imperfect free will you mean we need God and grace then sure. No Catholic would deny that.
In the end, grace...free will..have at their heart God, Who is a Mystery. So in over-defining we may make a mistake or have a misunderstanding.