^ 40mg seems like way too much for someone without a tolerance, if done all at once that would be a very uncomfortable dose for someone that's naive . I would definitely go with 5mg first, better to start with 5mg and possibly waste it than start with a higher dose and be sick or nodding too hard. If 5mg doesn't do it for you then wait at least a few hours then try 10mg and so on.
Really I'd recommend not doing it at all and just using weed to chill and play games, if you have a good relationship with Mary it would be better to stick with that. Plus although opiates are good for pretty much anything that doesn't require being alert, weed is better for watching movies or playing games. IMO it gives me a more intense appreciation for the story and/or the artwork and it also makes me feel more like I'm actually the character in games, it makes for a more rich experience in all regards.