Greetings from Indonesia mattia_v,
Reef hoods AND muck sticks (aka pointers) are always good to bring to any Indonesian location. In the perfect world we would never touch, bump or do ANY damage to the reef, but unfortunately that's just not reality, so I feel these do the least amount of damage when used properly.
I prefer a single hook, it's easier to stow and easier to attach. It needs to be sturdy and I prefer a larger hook so you can actually hook in (on a dead piece of coral) and clear the corner, so it won't scrape and possible weaken the dead spot, you don't want it to break free when you're floating like a balloon in the water column. Have your dive guide show you how to use these properly, they do take some getting used to, but once you master it and think about where/when you are going to use it properly they're wonderful.
Think about the line and how much weight you are putting on it, do you wear a lot of weight? Do you have a big camera as well? If so, even if it's bouyant it will create additional drag on the line, are you streamline. You could be in strong currents and that these factors will put more stress on the line. Also, I like my line a little longer so I have room to clear the reef, seafans, hydroids...etc. The dead piece you hook into may have living marine life around so you want to be able to clear that. I have a 2 meter line which I've put some knotts (w/loops) in and adjust as needed. I then use the knotts to pull myself down the line to hook and rehook as needed.
My clip looks like a baby diaper pin and has a squeeze handle on it to attach to a D-ring. You can always get a brass or steel snap clip w/swivel. Speaking of attching to a D-ring, I like to use the D-ring near my chest vs. waist.
In addition to the Reef hook, get a muck stick to use when the current isn't strong. With this you can get in to look at something and support yourself with out touching or laying on the reef. Many won't agree with me about using these or hooks at all, but unfortunately people WILL touch the reef, in my opion I'd rather they use a small stick or hook vs. fingers or even their whole hands w/suncreen on them.
Again, always look where you are attaching or putting your stick down. Only hook to dead coral and make sure there are no critters you are about to stab w/your pointer. If you can't get in and out safely and without damage to look at something, than it's not worth looking at (IMHO).
Have a fantastic time in R4. Hope this has helped.
Cheers,
