Re: weapon training for lower ranks
If "Jo-dori" and "tachi dori" mean Randori with Jo or Bokken. And By Randori you mean free-play with both sides attacking and defending freely, then I believe you are skipping a few stages here:
After Suburi, one should learn basic paired exercises (Kata), just like we do with un-armed Aikido.
Randori should start after a while of this, when one can perform a pre-ordained multi-attack paired exercise with reasonable control and accuracy. This normally takes ~1/2 a year or so. Even then, one should start with simpler variation (only one side attacks, the other defends, going up to allowing the other to counter ...)