Keep in mind that you need a Weber 32/36 that is JETTED for an Opel. Just off the shelf they are not ideally set up for our cars.
OGTS sells Webers with the correct jetting for your car, I strongly suggest you start off with a brand new, properly jetted, carb from them.
I am not a believer in trying to make a Weber carb last 100 years, as some guys do. Maybe they can do it, but I can't. Your carb is the brains of your engine, a new carb doesn't have any of the potential fluff-ups that the previous owner might have done. I have had carbs where the PO had drilled out the jets and passageways, floats that are hopelessly out of adjustment, and mixture screws that had been overtightened and broke the seats, so that they could never be made to run right. Plus, you should buy a basic rebuild kit when you get any used carb to replace the rubber o-ring seals and several rubber diaphragms that dry out or tear inside.
Get a new one from OGTS.