The Rogue amps perform really well from their 4 ohm taps into 8 ohm nominal speakers, so a 3 ohm dip shouldn’t be any problem when running from those taps. But the Stereo 100 should perform better overall, if you can go there.
100 Watts, even sacrificing a little of that for running 4 ohm taps into 8 ohms (this mismatch will generally sacrifice some power in exchange for lower distortion and better bass), should be enough for you 93dB speakers.
I like the A21 (owned one in the past) but I think the Rogue amps will be more enjoyable. They also bring a lot of flexibility for tube rolling, etc.