Well if you are going to work as an Instrumentation Engineer you will be offered around 20K basic salary (excluding any over-time or any other thing). Your post will be in the senior staff, so you don't actually have any chance of recieving over-time, but you can do it if you want. I would recommend you do like 2 or 3 hours a week over-time, because you will get QR 100+ per hour of over time, now thats good as you will get a high boost of income.

You will also receive a hell amount of bonuses, first of all, you be offered a villa if your going to live inside Al-Khor community, then you will have an Annual vacation of around 35 days (Excluding your weekends, which is friday, saturday and other holidays you'll get), and you will be paid around 16,000 riyals for your tickets, which will be your choice if you want to save money choose a cheap airline, and you will also recieve your basic salary and some more for your vacation expenses. There are much more benefits than these, so you'll love it. please do reply back to me and tell me your basic salary and other stuff, coz i want to know more, and want to know if my estimations were correct.

And try to negotiate your salary to the highest. Hope i've helped you.