As a new into diving I bought small dive torch (one 2665 battery) but now I'm confused how to connect it to my harnes. Via the long cord (and keep it always connected during the dive) or tightned close to bolt snap and deatach it if used?
Get a soft goodman handle (countless options).
Attach the divelight on top of your hand and forget about clipping and lanyards. Backup lights you can clip to your harness.
Pros and cons are clear: Always attached cannot fall to the deep, but strugling with long cord,
A soft goodman handle keeps your light always attached and has no cord. A hard (aluminum) goodman handle comes with the same benefits but is easier to don/doff while it might require slightly more focus because it sits more loosely (being made out of metal it does not quite fit like a glove). Anyway, you will want a goodman handle of some sort and you can later finetune it to your liking.
short attachement is more handy but can be easily lost.
and yet almost all technical divers prefer a canister light with that long cord.
I know that sump divers do not use canister lights that often, though - because of the environment.
You are not a sump diver.
No. Just no. Keep things simple.
That thing has too many features. Will it kill you? No! Will you love it while diving? No!
- Just my opinion.
(I know this type of carabines is wrong, but can be easily replaced by standard scuba bolt snaps.)
No, it's not about the carabiners. Carabiners are really problematic if you have two or three of them (or more!) and they become entangled. You'll have to be god of carabiners to untangle that mess... but a single lonely carabiner is unlikely to wreck your dive or to kill you. OK, in cave diving some individuals have managed to clip their carabiners onto the cave line - quite an achievement indeed - but you are not a cave diver.
You should only focus on keeping things SIMPLE.
Goodman handles are simple. Attach and forget type of light attachment.