I used ML SL3's with a Krell KAV 300i on the bottom and BAT VK60 mono's on the top and the sound was great, much better than either set of amps alone. I could have easily gotten by with a single VK60 on the top which is closer to your 30W Joule Electra. You will do fine on small scale jazz but may want a little more oomph on louder stuff. Try it first before you commit to anything.
I found that having a preamp on the Krell was necessary to balance the highs/lows since the amps were so different. Your pair may be close enough to get by without.
I found that having a preamp on the Krell was necessary to balance the highs/lows since the amps were so different. Your pair may be close enough to get by without.