I slid the longeron into place for a trial fit. Here you can see where the F-711 intersects the longeron. You might think it's crazy to cut a notch in something as crucial structure-wise as the longeron, but remember that this is about 6" from the aft end. The rest remains totally intact.
Did the same thing with the left longeron.
The three bulkheads that the longerons actually pass through (F-706, F-707, F-708) have notches pre-cut for the angle. Unfortunately, the notches aren't wide enough! I don't understand why Van's would go undersized on this, but they did. I took the Dremel to each slot and enlarged it to 1/8", using a small piece of scrap angle to test the fit.
The next step is going to be priming the longerons, since I anticipate that once they go into place, they'll be there to stay. You never know with these new-fangled Van's kits, but I read ahead and saw nothing about removing the longerons for prep later...so I want to be prepared. Anyway, it's too late in the day and too chilly to break out the primer at this point. I'll wait until it's sunny tomorrow mid-day.
In the meantime, I clecoed the forward half of the F-704 bulkhead in place. This whole center section is quite the heavy thing now. Pretty beefy...if it's this stiff and beefy now, it's going to be incredibly sturdy in the air. It had better be since I'm going to be throwing this sucker around when doing aerobatics.
That's about it for the night. Tomorrow I'll prime the longerons, and I might even get these things flipped over and joined tomorrow. We'll see.