You don’t need to fear PTU. I’ve met a few people who have been on it successfully. Even methimazole isn’t free of side effects – it’s just a little safer than PTU. Another reason that PTU is out of favor – something that you mentioned – is that you have to take it multiple times a day, while methimazole can be taken once a day. That alone would make methimazole the preferred drug, since patient compliance is really important for best results.
Good for you for taking steps to quit smoking. I’m glad you’re aware of the increased risks of Thyroid Eye Disease for smokers. You should also be aware that it will improve your outcome if you’re able to have a thyroidectomy. Smoking constricts blood vessels and impairs healing from surgery. Good luck with those last two cigarettes.