I have been on them for a few months, I was told about the weight gain, so far touch lots of wood I don't think I have put weight on or if any very little. With gliclazide you can't skip a meal like you could with metformin, you need to eat to feed the meter or risk hypos.
Think if am not careful will end up putting weight, though my food intake and type of food I eat has changed since being on gliclazide. A meter will also tell you what foods will cause you to spike in your BS, by regularly testing .
To start with I would test first thing in the morning when waking, then 2 hours after breakfast then pre meal and 2 hours after meals and last thing before bed in case you need to have a snack. You might need to do other random tests to identify if you have any problem times when your BS goes low and experience hypo symptoms.
Always have sweats like jelly babies, fruit pastels etc on you and in the car, as a just in case.
If you don't already have a meter, you will need to get one, which you can normally get free via the suppliers like Bayer, Abbott Medisense, Life Scan, Accu Chek etc. You could always be cheeky enough (politely) and ask for 2 meters one as a main meter and one for you to carry around with you.
You will then need to get a prescription for test strips, which you should be able to get as you are now on meds that can cause hypos, plus if you drive you are required to test before driving and every 2 hours until journey has finished. That uses up quite a few test strips with me.