A few points that I'm going to throw out:

1. I'm in the camp that there are too many Channeling differences to compare men to women. Strength is only one of the many measures we've seen that is incongruous. Why can a woman of little power weave a longer air bridge than a man? Why do women get both stronger and more dexterous when links are formed, rather than just stronger? Why can't men link for that matter! Rand could be a 400 on female scales for all we know! It's like measuring cubic feet vs. a metric ton... or It's like saying a woman can run 2 miles and a man can cycle 5 miles... that doesn't tell us a damn thing about how they compare ... they are just different.

2. The Logain quote makes no sense at all! Rand who is clearly stronger had no chance of breaking the shield held on him until it was down to 3 women! So the odds of Logain really being able to break that shield are slim unless the women were all Daigian weak.

3. Were is the quote saying Lanfear was 2x stronger than Elayne? All that is said is that Moiraine believes Aviendha and Egwene combined could match Lanfear, when neither Aviendha nor Egwene are at their full strength. But even if they were 120 vs. Lanfear's 100 they still don't have the skill necessary to survive the encounter... Alivia was probably over 200 when she faced Cyndane's 90 and still basically got her ass handed to her.

4. As I stated below, I believe the average AS are quite weak, it's the main characters that I think are stronger than you guys are giving them credit for. IMO an "average AS" is probably about a 25, with a weak one at 15 and a strong one 35 with a few outliers above that level. Looking at the women above that we have what a dozen in the AS ranks? With a thousand below it... if you throw in you must be a 30 to Travel it works for me ... then 3 "strong AS" would be necessary to hold a shield on the likes of Lanfear, or 2 "average AS" for Egwene, as we see in TGS.

In the end I see "effectiveness" as meaning Egwene can perform task X, which makes her as effective as a man who can also perform task X to the same degree... it has nothing to do with their relative strength to one another.

With that said, let's look at Semirhage being shielded... it took 3 women at all times, but Daigian was in the last link with Nesune and Erian (IIRC)... together they would be about 45 strength by your scales ... and probably shouldn't be strong enough to shield Semirhave who's probably upwards of 80-85! Unless you think someone can hold a shield on you when they are half your strength? IMO this 3-some would need to be a minimum of 60 to hold a shield on Semirhage, probably closer to 70 to be "taking no chances" as Cadsuane says.