Paint the whole tail red. That'd look nice. You could use white to checkerboard the rudder.
Your plan sounds nice too.
In either case, I'd extend the horizontal line on the fuselage all the way onto the rudder - maybe tapering it to a point before it runs off the rudder. That'll tie the whole thing together. Right now, that grey stripe just seems to end without any reason.
If it were mine, I would paint out the "tail thing" and then give it some thought. The problem with painting just the tail red, or any contrasting color, is that it makes the airplane look shorter. Shorter is the last thing most airplanes need visually. A stripe, like yours, continued to the tail, will help. If you do want to decorate the tail, you might consider trying a few themes, checkerboard or whatever, in tape or vinyl before committing to paint.
Here is the highly decorated stab on my '8':
John Clark ATP, CFI Art major, graphic design (really)
FAAST Team Representative
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
The rudder and vertical stab. It would balance the airplane - I believe if you have a lot of color on the nose of the airplane (you do), then you need a big splash of color on the tail to give it balance.
I'm no graphic designer, but I like the idea of a checkerboard rudder with solid red vert stabilizer and elevator / horizontal. I'd carry it forward somehow to keep the red tail from making the plane look shorter...
Then again, my plane is still not painted. Maybe this fall...
Many years ago, a friend told me to design the paint scheme so it flows, with the main objective to make it longer and have greater span. In looking at the RV's at Oshkosh it amazes me how many have schemes where the paint is just chopped off. Often looks like the wings from one plane on the fuselage from another and yet a tail group from somewhere else. (Stein's plane doesn't count. They did that intentionally)
This can be accomplished with a simple design or something more complex. AS someone noted, long lines on the fuselage help. It is only a matter of time and money. I recently had my 7 repainted and stuck to this goal.