Share 'Standing rigging lashings - how tight? - & how?!'

Hi everyone! I am sure many of you have some good ideas about this - how tight should the lashings for the standing rigging be? I have a Pahi 42 with conventional rig (ie bermudan cutter with boom). I am using dynema rope for all the lashings from shrouds and stays to chainplates etc. What I am puzzled by is that dynema doesn't stretch (or so I am told..) but I can't get my rigging to stay taught…