Once it's completed it surpasses his previous Shinigami powers, ya know, the entire premise of the LAA with Ichigo regaining and surpassing his Shinigami power. His previous Shinigami powers being on par with Res Yammy's AP while at just half power.
Here are the statements I found.
Iko saying Grimmjow is ass compared to him and Baraggan.
Narrator stating he'd lose to Baraggan.
Iko having reiatsu >= Baraggan, "if not greater" to me tho implies it's probably more.
Iko and Baraggan used to fight and Iko would stalemate Baraggan's Respira.
Yeah given those statements, I think it is saying Respira would just annihilate Grimmjow. Especially since when Iko makes those statements about Grimmjow < Baraggan, it's from the perspective of a Hollow who would fight and stalemate against Baraggan's Respira. So, when Iko is referring to Baraggan's power, it's probably his Respira. Imo that's more consistent anyway. Especially since CFYOW Grimmjow's GRC ~ CFYOW Ginjo's Getsuga, and we no LAA Shikai Ginjo's Getsuga evenly matched FB Shikai Ichigo's Getsuga. And the absolute lowest you can lowball FB Shikai Ichigo is still beyond FKT Bankai Ichigo, who's got strength beyond Res Yammy, who's obviously above Res Baraggan in terms of raw stats.