Her age would be augmented to a small degree given her tiny ability, especially since WOs lead harsher lives than an AS would ... and given that Bair, who cannot Channel is equally ancient in description, yet clearly younger than Sorilea I think it's safe to say that Sorilea has some bonus longevity.
As for outward physical signs, Sorilea does not look YOUNG, just no older than somewhat younger Bair, and the books do note Morgase retaining her youth more than one would expect, so that difference is also negligible.
The main difference is that, though channeling was not a primary WO concern, Sorilea almost certainly got FAR more channeler training than Morgase, simply because it was practically impossible to get LESS. She probably got more "training" and "practice" trying to wave a kerchief throughout ONE AFTERNOON than in the whole REST OF HER LIFE COMBINED. The mere fact Sorilea can grasp the Source at will shows more training than that; it does NOT necessarily show more strength.
I do not think a difference in their strengths clear at all, else I would not contend it is nonexistent. 
Morgase also exhibits ability to use the OP, after perhaps as little as half a days constant effort on top of half a days "training" decades earlier. Sure, waving a hanky is not much: But for an incredibly weak channeler who has only spent a ONE DAY IN HER WHOLE LIFE trying to channel, it is quite impressive. At least as much as an equally weak channeler simply adding her strength to others after decades or perhaps even a century or regular training and practice, even if channeling was only an incidental part of that experience.
You keep making the assertion that she only spend ONE day ever training, which is patently unprovable. As a future High Seat (as she was when she went to the Tower), she would have been treated quite well when her limited ability was discovered and I'm certain that the AS would have been more willing to use this time to build a strong foundational relationship with a powerful Noble, who they would have suspected would be next in line to be Queen should anything happen to the Daughter Heir.
Point being she spent an awful lot of time in the Tower and reflects on having chats with various AS during her time ... no other Novice expresses such relationships. She would have gotten more training than you outline in any case as she would have died without learning at least the basics of control. Fact is she is so weak that grasping the Source is basically the limit of her ability.
Sorilea has more.
Yes, Cadsuane suspects VERY incorrectly: From what we are told of Sorileas history and family she is probably only a few years past 100, if that. So Caddy was off by a factor of 3, indicating either gauging strength and/or its effect on slowing (most likely the latter) is far from an exact science. Yet Sorilea LOOKS very old despite being around 100 and her apparent aging slowed by channeling; no one would call Bair young, nor even middle aged, so Sorilea has not slowed MUCH, and Morgase has slowed enough--despite having only channeled ONCE, BRIEFLY, before her captivity--it is noticeable even by her early forties. So if there is a difference between their strengths (and, realistically, it is extremely implausible their strengths would be exactly equal) the available evidence strongly argues it is negligible.
As Fionwe commented, RJ has stated that the WO appear older and live shorter lives because of living in the Waste. Sorilea could be as old as 150 from the information we have. Cadsuane has encountered at least one other "toothless wilder" in her career so it seems likely that she has some idea that there is something different about the way they age and she has clearly realized that AS ages vary based on their strength in the power. So her assumption that Sorilea may be as old as she is isn't coming from a total guess, she's got enough information to factor in strength adding more longevity, aging process looking different to AS than to Wilders and Sorilea's obvious looks. Point being she's seems strong enough in the Power to have a little bit of slowing, more than what we've seen with Morgase who probably won't live much longer than a normal woman.
