Any experience with the new Severne Enigma boom, in particular adjusting the 160 length from SDM to RDM ?

Do you mean the 160-210 freemove enigma? I use that and the 170-220 size. They fit securely on both rdm and sdm masts, just by adjusting the inhaul rope length, no issues swapping between rdm or sdm masts

I just tighten the rope.

Yes, looking to use it with RDM Severne Blue and Gorilla RDM. Thanks for the info. Much appreciated