Vince was more concerned about what form weight was gained, as opposed to just gaining weight. So, at least in my case, his suggestions and plans for me included more fats and protein, but less carbs to ensure I gained quality, lean muscle and not fat.
How I determine the amount of carbs I need now is by starting low and gradually increasing. If I should start feeling lethargic, or get bloated I know I'm taking in too much carbs. If you start getting fat... you're taking in too much.
Remember to be patient when trying to gain/lose weight. If you were to gain one pound a week (4 pounds of muscle a month), you would be gaining an average of .14 lbs of unnoticable muscle a day. But over a year (should you stay consistent) that would equal to 52 pounds of very noticable muscle weight gained.
The last 36 - 48 hours before a competition I take in one yam every hour until the evening competition. Yes, on the hour every hour - one yam. My girlfriend or alarm would wake me up throughout the night every hour the night before competition and I would eat. Simple carb loading. Sometimes it worked wonderfully, others poorly - I've never mastered it.