TLDR: Change falling damage to 1M/2 and use Total Warfare's difficulties for pilots passing out (if they don't have +1 to their WIL linked bonus, bump their difficulties up or down to match the change).
aToW tells us to use 6's for the unknown stats of people on the tactical scale. So our theoretical pilot has 12 Wounds he can take before he is D.E.D. Dead. Falling inflicts 1m/3 against pilots. If our pilot is in his cooling vest, He gains no protections (as the 1m AP cancels out the 1 armor the cooling vest gives in melee). Thus our boy dies on his fourth fall. Thats 2 hits less than our mechwarrior in TW. Our aToW mechwarrior does fair better against mech head shots, only taking 2 damage (as the cooling vest has a ballistic BAR of 2). Thus he could survive 6 headshots (if his mech could take 6 headshots without having it's head blown off with him in it).
Now, there is one big hitch in this whole thing: the damage numbers for falling are off. If you look at the standard falling damage rules you will see you take damage equal to 0.2 x meters falls. Mechs fall 1 hex when they go down. 1 hex is six meters tall. Thus we plug in the numbers and get 1.2 damage (which rounds up to 2). The AP of the fall is equal to 0.1 x meters fallen, an so equals 0.6 (rounds up to 1). Our final value is 1M/2. With this damage code we take 2 wounds per fall and will die in 6 falls (where we take damage, as you can still make a pilot roll to avoid taking damage). Now that we are dying in equal fashion to TW mechwarrior, lets look at passing out.
As I previously mentioned, TW characters have a 6 in all their attributes. This means they get +1 for linked attributes. Since we are taking 2 damage, our wound modifier will be -1. So far we are at a wash, but remember that we are wearing a helmet and strapped in, not falling like a rag doll onto concrete. We can at least say conditions are good (we're sitting on a command couch which must have some level of padding). That gains us a +1, meaning we are now in the positive. I'd take it a step further though and say that since we haven't fallen yet and we have specific gear which is meant to keep us safe in a crash (safety harness/crash webbing and a helmet) we have it very easy. Thus we net another +3 for a total of +4 to our roll to not knock out. We need to roll a 3, which is identical to what Total Warfare pilots have to make on their first roll.
The next time we fall and take damage we have taken 4 damage. This is above 25%, but below 50%, so we now have a -2 for our wound penalty. Given the nature of falling hard repeatedly, out gear will be less effective and we will be more vulnerable. Thus our difficulty will drop to merely easy. Final calculations are thusly +1 (linked attribute) -2 (Wound penalty) +1 (Good conditions) +1 (easy) = +1. We need to roll a 6 or better, which is one higher than our TW compatriot.
Damaging fall #3 brings us up to 6 wounds taken. As this is 50% of our total wounds, there is no increase in penalty. Our easy check becomes average though, meaning we're going to lose 1 to our total. Our modifier is +0 and we need to roll a 7. This is equal to the third roll from the TW pilot.
Damaging fall #4 sees our wounds taken rise to 8. Now above half, but less than 75%, our wound penalty rises to -3. Further, we slide another down the scale from average to difficult. Thats another 1 off our modifier. We end with a -2 modifier and need to roll a 9 or higher. We're actually doing better than out TW pilot, he needs a 10 this roll.
Damaging fall #5. Our wounds are at 10. We have breached 75% and thus are up to a -4 wound penalty. The difficulty has become very difficult and goes from -1 to -3. Adding up our total looks grim. Our pilot has +1 (linked attribute) + 1 (good conditions) -4 (wound penalties) -3 (Very difficult) = -5 modifier, we need a 12! This is worse than our TW pilot who need an 11.
Damaging fall #6, both pilots die.
Using this model our numbers are within 1 of the Total Warfare numbers for every roll. It is easier once and more difficult twice. Do remember though, that aToW characters have edge that TW pilots don't, so this isn't as big of a factor as you might think. What it does illustrate though, is that you could use the TW difficulties with almost no appreciable difference to the outcomes. The only adjustment needed would be to account for lower or higher linked attribute modifiers.
You could also just asses the difficulty once. Rather than going from +3 to -3 on the difficulty, you could choose to use a +0 every time instead. Players would thus need 6's to stay conscious (including the wound penalty) on the first roll. Thats a 72% chance to make your roll. Roll 2 & 3 would have a 58% chance of success. Roll 4 would have a 42% chance of success. Roll 5 would have a 28% chance of success.
Using TW's numbers, you'd have 92% on roll 1, 83% on 2, 58% on 3, 17% on 4, & 8% on 5.
Using my AtoW method we need 92% on 1, 72% on 2, 58% on 3, 28% on 4, & 3% on 5.
Looking at how the three ways to do it play out, I'd say your best bet is to stick with TW's numbers. With them and my modified fall damage you should have pilots who can take a few hits, but pass out before they flatline. Pilots who want to push the limit can leverage their edge to do so.
