Twin set advice required.

I've just changed to using a twin set and would like some advice on a couple
of issues I have.

1) While I can reach and turn of my valves I find them difficult to get a
grip of.
I believe I saw something about being able to get bigger handles.
Anyone know where from?

2) It takes quite a few turns to close the end valves, I guess it takes me
over 30 secs, during which I'm loosing precious air.
I know you can set the centre valve so it only needs 1 turn to close
off but what about the end valves?
I discussed this with a few people at my dive club and they said leave
the end valves open.
No-one could give me a reason why it isn't safe to keep all the valves
just 1 turn open?
Perhaps the smaller aperture makes a free flow more likely due to gas
expansion/cooling?
Or is it just the chance of turning the wrong way?
What do other twin set users do?

I know I could solve all this by inverting but I don't fancy the longer
cables floating about and getting tangled during kit-up.

Thanks in advance,

Ron MacRae.