Ok, since you asked for info, I'll give you my 'opinion'.
Since you have built the empennage, you should be handy enough with the tools and procedures to build any part of the kit that you choose. As a first time builder, I am following Van's instructions including the order of construction exactly BUT, if I had it to do again, I'd build the fuselage next as, in my opinion, the fuselage, finish kit, engine and avionics install, amounts to probably at least 90% of the work that it takes to complete a RV-12.
My mentor who has built an RV-8 and helped on a few others and I finished the empennage and wings in about 3 months of part time work. The fuselage structure is a lot more complicated - the wiring in particular.
The finish kit presented the challenge of learning to use fiberglass and epoxy. I probably have more the 100 hours in doing the fiberglass work involved in the canopy, cowling and wheel pants - a lot of learning what not to do! I'd say that sanding fiberglass parts has taken 2/3s of whatever time I've put into the fiberglass work. My mentor says that I'm spending too much time sanding but it's my build of my airplane right?
We are installing avionics at this time and that presents another challenge to me. We had the wiring diagram blown up by a blueprint shop so that we could read the numbers of the pins of the connectors. I admire anyone who finds Van's wiring diagram of sufficient size to use it!
So, I suggest that you put the wing kit away after inventorying it, order the fuselage kit, and build the fuselage kit, finish kit, wiring, avionic and engine install next. Build the wings last - they are really in the way even in a hanger - in my opinion.
I heard that two guys built an RV-12 in 67 days! That is amazing and I'd like to shake their hands some day.
My next build will be an RV-9 or RV-9A and I'll build the fuselage first. Hope this helps you. Best to you, Ed Eliot