Turns out many middle eastern toilets can’t handle toilet paper.

It’s more about toilet paper than plumbing. Toilet paper has to easily dissolve in water, otherwise you can clog any toilet, be it western or eastern.

10% is too low. Usually they won’t be against paying you the same they are paying your current employer for your services, so you can safely do 20% raise ( your employer charges more, of course, but there are other costs involved to set up and run the operation).