As a medieval fencing novice, what is called "cience of the sword", I got somewhat frustrated as what I did expect.
That was noble dueling, with what we call longsword, bastard, hand-and-a-half or even two handed sword. They are all always helded with both hands as is your opponent.
As "noble" dueling there was some etiquette, althought those duels could be deadly. Just to say, low blows (lets say below hips) were not frequent at all. And the best blows are those trusting the point against the opponent (they are the fastest attacks while keeping you shielded and under control of the other sword, both by your own sword
) so "puncture" crits will be much more usual than "slash".
There are slash attacks, of course, 7 that I can remember but are usually used in "series" of blows. You know ... hint that, test this, trust hard and if you are parried contra-attack with that specific slash. Just to say that in one-on-one fight it's quite easy to see and parry a direct slash attack, and with nice chances of having a deadly contra-attack.
The main target is at the collarbone height and a lot of contras are against the head.
This to say that even serious medieval fencing doesn't reflect the mayhem of an open medieval fight involving many fighters. I've seen also some practice of foil ans dagger combo vs idem and they are rather awkward, both fighters crouching and hiding themselves behind their weapons guards. But it's amazing how much can shield the foil's guard, vs some of it's kind really. Thats what's must odd of fantasy, the bizarre combinations of weapons and armours. The are wearing chain, forget the foil and the short sword. Are they unarmored? I choose foil well before a mace.
So I must say that, in order to assign chances of hitting sides, you should evaluate the style of both fighters and the weapons they are using because they will always tend to keep as much lower profile as possible and give a fast attack. The faster the better.
Just my two cents