There's more you can do to steady the idle, I stand behind the position " there is never a reason to disconnect the ISCV beyond troubleshooting".
I have bored TBs, completely removed secondary plates/rods/sensor, and big huge cams with big huge intake ports meaning very low airspeed at idle and ISCV still holds a steady 1050 RPM idle +/- 40 RPM.
Part 1 is ensure the TBs are properly balanced.
Part 2 is to adjust Primary TPS to 0.68v instead of 0.6v.
Part 3 if you're still seeing hunting/stalling, is screw in the throttle stop slightly, reset ISCV again.
Part 4 if you still have hunting is shaping a low timing advance valley in the tune file. This causes the engine to want to idle at the RPM where the lowest timing is. This step was crucial on the built motor, to get it behave.
Past that....you have a broken piece of hardware somewhere.
My "Custom" throttle stop, I got sick of the Triumph tomfoolery and modified this gold bolt to the exact correct length.
Still connected ISCV:
