I agree that Rand was obviously still growing throuout the series, that is clear, but the amount of growth is impossible to really define. I find it hard to believe that 4 Forsaken would be convinced of ganging up on him if he wasnt already in their strength class. There is the quote about "risking his strength" during this time and discussion around his strength among these four ... Even they seem surprised by how strong he already is and don't seem eager to face him due to it. They are clearly trying to figure out how dangerous he is in the early books since they aren't clear how much of LTT is still in him ... If he was significantly weaker than them during this time as well as significantly less skilled they would have gone after him much more directly, they would all assume he would eventually get stronger.

But you are correct about both Aginor and Asmodean face offs ... Although the Eye scene reads to me like Rand could manage power Aginor could not and during the fight with Asmodean there is the pre-CK duel which makes them seem pretty equal ... But I do concede that Asmodean was likely more concerned with getting to the CK than the fight itself.