RE : Mother Talzin (see details)

Suppose MT absorbed the raw Force energy from the Dagoyan Masters of Bardotta etc and Suppose she successfully absorbed all the Masters, without getting derailed by Mace Windu and Jar Jar Binks etc how powerful will that make her?

More powerful than Sidious.

Yeah, Sidious saw her as a direct threat even when she was relatively de-powered in Son of Dathomir. If she had succeeded in her efforts to rob the Dagoyans of their power, she'd be the strongest living Force wielder during TCW, surpassing Yoda, Sidious, Mace, ect.