I figured that they were both below the level of Aginor/Sammael, and certainly below Demandred. The reason I say this is that Rand thinks of Taim as being close to his strength in LoC, and he didn't hit his potential until the Cleansing.

The thing with Flinn, now that I think about it, is that he MUST be stronger than 40. He's in a circle with two AS at the Cleansing, (I don't remember who, exactly, but I figure they're both slightly above average for AS strength, so let's say 20 each) and with the linking penalty, their combined strengths would still have to be above 90 to give credence to Demandred's thought that their weaving is as strong as his own. So maybe Flinn's closer to a 55? Maybe his strength is part of why he's the best at Healing that we've seen yet (which we know, at least seems to be the case, since Cadsuane considers Samitsu "the best alive at Healing—at least until the appearance of Damer Flinn" (CoT 671) and Cadsuane knows Nynaeve as well).