I have the following sails
Severne Motos 5.2, 6.4 and 7.8
Severne Gator 6.5
Foil Glide 2 6.0 and 7.0
I have an Enigma 160 boom which all the above fit on. However I was toying with the luxury of getting another boom, quick kit swap in variable conditions or fin to foil gear etc
I had been keeping an eye out for a 170 boom but a 180 Enigma has come up locally at a decent price.
With the Moto 7.8 and Foil Glide 7.0 being 200+ and all the other sails (bar the small 5.2) having a boom size of 184-190 the Enigma 180 would rig them all.
Maybe over-boomed but looking at the spec sheet the weight of the 180 (2.68kg) is barely heavier than the 170 (2.61kg) so the swing weight might not be much different?
Would anyone with experience of enigma booms have any comment or reason to avoid the 180 and wait for a 170?
Well that is weird...
On a mobile, in the UK at least, when viewed in a normal orientation, the weights are as above and there's no significant difference between the 170&180.
I just turned the mobile into landscape to take a screenshot so everything was visible and the weights for all but two Enigma booms changed!! Making there almost half a kilo difference between the 170 / 180. 

Is the diameter and clew end the same in both?
I have just went through the UK windsurf shop websites and the ones that have the weight of the enigma booms have the weights in my original post (2.61 and 2.68kg). So I am confused.
But they're meant to have the same grip diameter and I believe both have pulleys for adjustable outhaul
the 170 is an inside boom tail
The 180 is an outside boom tail