Weighting for dry suit

So I've seen it said that when diving sides the diver should be weighted so that they're neutral without cylinders attached. I think this comes from cave diving so that if a restriction is encountered that requires one of both cylinders removed the diver's buoyancy stays manageable.

Does anybody know of any other reasons?

Reason I ask is that in the UK I'm normally in a drysuit with fluffy underwear (for warmth you understand). It would take a huge amount of lead to get me neutral and leave me with a comfortable amount of air in my suit. Hence I use steel cylinders that are always negative to take some lead off.

Anybody see a problem with this for open water? What do others do?

This does not apply to you directly but it does answer the question for me:

I want to use standard 80s because I want to be able to use multiple tanks (including odd numbers, two on ones side one on the other), and clip off dead tank to trail me. SInce standard 80's are buoyant (depending on the reg, and whether they are Luxfer or Catalina) from about half full;, and I might end up trailing two empties, I want the weight on me.

Of course single tank sidemount kinds of needs 80s.

Given these facts, most AL80s divers are going to carry their weight on the body.

That does indeed make sense for your setup.

You seem to have a wealth of options that side of the Atlantic when it comes to cylinders. Over here you could go a lifetime without seeing an aluminium one.