Single or dual weapon?

Basically the title, is it advisable to spec into both JB and blades or pick one or the other at this phase in the game?

It is doable, but it requires being very picky with your Skill Tree. Here is a Bo/Hu Tree from Ryutensei's Bouncer Guide that is built for both weapons utilizing Break Stance for SBs and Elemental Stance for JBs. As you can see, there is very little wiggle room for what you can adjust on there to get the most effective Skills.