If you're going to have an endoscopy on Monday, you'd be wise not to irritate your esophagus and throat with smoke until that's over. I'm assuming you're going to be cleaning out your gut, too, in advance of the colonsocopy, so eating cannabis in food isn't really an option for you, either.

You sound like you're one of those who's bound and determined to smoke no matter what, so you may not heed this advice anyway. The reason to keep your esophagus unirritated is because that tube is going to scrape you on its way down, and you don't want any unnecessary irritation in there to increase the possibility of bleeding or potentially obscure any ulcerations or problems they may be looking at with the scope. I wouldn't drink alcohol, either, by the way. Interaction with the sedative they give you is also a concern, but I think the greater concern is to minimize irritation.

Tell your gastroenterologist how much cannabis (or cigarettes) you smoke and tell your anesthesiologist how much cannabis you've had within the last week or so. They need to have that information so they can treat you appropriately.