In the manga, Senjumaru did not employ Bankai. The character's abilities and actions were depicted differently without resorting to this particular power.
I'd suggest checking manga forums or dedicated Bleach fan sites. They often have detailed breakdowns and recommendations on where to pick up after a specific part. Sometimes, the author or official sources might provide cues as well.
Naruto might use Bankai in a more physical and direct way compared to Bleach characters. Since Naruto is used to combat with his body and chakra - enhanced attacks, his Bankai could be more like a physical transformation rather than the more spiritual manifestations in Bleach. For example, instead of a spectral form, his Bankai could be a physical enhancement of his body with the Zanpakuto's power.
Honestly, I don't know when the TYBW manga starts. But you could search manga databases or ask in manga enthusiast communities to get the details you need.