I would say the BB and SBB would make more of a difference with less sensitive speakers as yours are. My speakers are 92db and I got the SBB to drive the 15” woofers of my Spatial M3 Sapphires. Yours rated at 83db would surely benefit from the additional PSU IMO. I would reach out to Andreas from Octave who is extremely helpful and will not try to over sell you.
How loud do you usually listen?