I did not read all the replies but my gut reaction to OP question:
- How does it taxi, good? Stop worrying fly more.
- How does if fly, good? Stop worrying fly more.
These single push pull rod with spring cartridge tail wheel steering setups look cool and in general work OK, but the length has to be right. You did the right thing in my opinion modifying length. Your observation is likely right. I would not do anything else if it it operates on ground and air normally. You can always go back to cheap chains, they look kind of crude, cost you based on SWAG 0.01 Kt. (Scientific Wild A Guessing). BTW I have had one of these before and it was fine, although I read somewhere at some time one of these spring rods came apart? This is from a fuzzy memory and don't know if it was this brand. Preflight it carefully each time as you would chains.
Question did it ever fly straight? Not telling you do do this, how does it fly with link removed, or if you had chains originally, how did it fly? Was it skidding/slipping than? Just curious, rhetorical question.
Question did you ever call the manufacture? They state range of adjustment is 12.25 to 13.125 inches. Did you measure that? Again rhetorical questions. It is possible your tailwheel stinger was installed into the socket a little deeper? I don't know, but inquiring minds might wonder. Again see 1) and 2) above.
As far as your slip/skid ball, most RV's need a rudder wedge to be perfectly coordinated in flight in one flight condition, say Straight n Level, normal cruise speed, 75% power, with feet flat on floor*. There is never a perfectly rigging plane, any plane. A flight club C-182 I teach in, has cockpit elevator and rudder trim control. Obviously, trim changes all the time with flight condition, pitch, power, pitch, bank, speed. Since we do not have rudder trim (except fixed but some have fitted inflight controllable rudder trim), the ball will be out of center, without rudder trim or pilot input, resting big toe on the pedal. Obviously but it's not a jet with yaw dampers. Ever fly a piper cub?
My point don't get to OCD about it, but I do think your cockeyed tail wheel was a factor. The standard is rudder straight, tail wheel straight, not. It's not Rocket Surgery or Brain Engineering. (see what I did there).
* Tip for those who never learned this trick, rest feet on rudder pedals in cruise to damping yaw in turbulence. More over if there is any issue with say tailwheel driving the rudder, it takes it out right now. That big rudder is just floating out there like a flag on a poll. Resting big toes on rudder pedals increases yaw stability.
I typically rest my feet on rudder pedals in cruise just so a little turbulence does not let plane yaw as easily with free floating rudder. Flying freight in piston twins decades ago, in turbulence you wallowed around badly, but you can actually be a human yaw damper and counter the Dutch roll in turbulence (yaw roll coupling). You actively use rudders in cruise, like flying a tailwheel plane on landing, happy feet, to dampen or counter yaw, thus reducing Dutch roll. Takes timing, deft touch and practice. Not a big issue with RV's but they do dance in turbulence. At min plop you size 12 extra wide's on the rudder pedals and hold rudder straight in cruise. The period or frequency of the roll yaw couple oscillations in twins is slower than a single engine RV BTW.
PS anyone decides they want to test their RV's Vne at high altitudes (remember Vne is true airspeed not indicated). Mke sure you have firm grip on stick and feet firmly on rudder pedals (especially the RV-4 and RV-6 with un balanced rudders). I think that is in Van's documents? It has been written about many many times. There are some scary stories over the decades in the old RVator news letter.
