If you are having trouble keeping your round reed weaving (esp. the 4 & 5 double-rod or 2-ply weaving: O2U2 & O3U2) under control, try these tips:
Pull any slack out of the weaver with every "stitch" you make. I consider a "stitch" the motion that one weaver makes as it goes in front of and behind of a spoke. I give a small tug on the weaver as I go in front of a spoke/s and then lay it behind a spoke/s. Don't pull hard enough to affect the shape (unless you are making the shape move into a smaller diameter [and you should also be pushing inward on the spokes] and then you must also be compressing the rows! See below.) just enough to pull out any slack. You should feel a little give and then the weaver comes to a stop. Stop when you feel the stop.
Make sure the spokes are damp to wet and grasp several in one hand. Position your other hand with the fingers in between the spokes, against the weaving. Pull up with the spoke hand and push down with your fingers. I compress the rows about every 2-3 "stitches" (the complete motion that one weaver makes before picking up the next weaver). I always do a 4 or 5 rod wale in RR, O2U2 or O3U2 patterns, which are harder to compress than a O2U1 pattern. This is why I stress that the spokes need to be wet or damp. I keep them damp all the way through anyway becuase of the different nature of the beast.