Offsetting Side Turrets

[RedLancer]

Is there a simple guide somewhere on how to offset side turrets to create an HMS Invincible or HMS Hercules?  My attempts are a bit haphazard and I can't work out what I'm doing wrong.

[Cpt.Hissy]

Are you asking how to balance weights, or how to place turrets asymmetrically?

For latter, a way i know is to place one (gets you a pair), then take auto-placed symmetrical copy and move/delete it, original should stay in place then.

[RedLancer]

It's the latter - but as I do sometimes both turrets vanish. 

Is it best to place two sets and then delete one of each pair or place one pair and try and move them?  What is the best way to do that in detail i.e. hold down left mouse  button as an example.