Ruben,
OA operate their own charters on Halaniyat but share resource (boats, accommodation etc).
No Boundaries insists on PE10 but not the other operators. I personally use PE8 and although I've been occasionally undergunned the same thing can be said for PE10. In my opinion, not many GT fisherman, even experienced ones, are able to safely put enough pressure on a big fish to make an appreciable difference to success rates. PE8 is also much easier to cast, metre for metre and that's a key consideration. As a huge generalization, the guy that casts furthest keeps his lure in the strike zone longest and gets the most hits, it's not rocket science.
Read every word of Brandon's preamble to this forum, both in terms of tackle and preparation. It's GT fishing 101. There's nothing particularly unique about Southern Oman other than a comparatively high incidence of very big fish.
First rule, buy good quality. Most people choose a PE8-10 all rounder as a rod, between say 7'6 and 8 foot. The 7'6" rod will be easier when you hook up but the 8' rod will let you cast further more easily (thereby covering more ground or making it easier to hit the 'spot'). Lure weights up to 200g but be aware that rod makers famously over rate their rods. Budget will determine which brand and model you can get.
I personally wouldn't skimp on reels. I think there's two choices...Shimano Stella or the new Daiwa Saltigas (which I haven't personally tried or seen, just based on reports). Beg, borrow, steal or buy second hand from a reliable source. I know guys that claim that their lesser reel works fine but not with truly big GTs, at least not more than once or twice. There was a 63kg beast put on the deck last week, the rod was a mid level Hots 77XH (good choice that one) but there was no compromise on the reel.
Lures...if I had to take just 3 lures with me to Halaniyat it would be a 150/180g popper, a 160/200g floating stickbait and a big pencil. That's not hard and fast of course, I've seen big fish caught on 120g lures and, at times, a sinking stickbait is handy as well.
DO NOT SKIMP ON TERMINALS. The absolute best hooks, swivels and split rings you can buy...period.
There are many other things that make up the tackle for a trip. Leader, pliers, gloves..etc etc but at least what I've given you is a start.
Once you get your rod, reel and a lure or two take it down the beach and give it a blast. Like I said earlier, the best casters get the better opportunities and you don't need to be on the boat or in a shop (or on the internet) to get that part of your preparation going.
That time of year also brings a good chance of a sailfish and probably one of the best topwater Amberjack bites anywhere in the world but that's all for another discussion.
Above all, have fun
Regards,
Trev