Don't listen to Zcomp. Why, because every body is different.

THC half-life varies from 0.8 days to 10 days, depending on the person. It depends on gentics, body fat percentage, diet, physical activity level, smoking history, etc.

"We" as Zcomp puts it, aren't just concerned with the last 4 weeks. You smoking history is very important.

Drinking lots of water days and days before the test won't help flush you out. Very little THC metabolites are eliminated through sweat. What is important is calories burned. Being a bodybuilder your basal metabolic rate is probably higher than most because of extra muscle mass so that is good but it is about calories burned not how much you sweat.

You may be clean in 7-10 days and you may dilute but I would use your wife's urine and sub and in the meantime practice, practice, practice. Choose your container and practice with 2 ounces of water. Get it to temp then secure it and check the temp at 30 minutes, 1 hour, 2hours, etc. When you get it consistently between 90-100 degrees, repeat on the day o the test. Make sure you read the substitution sticky. Killerweed gave you some good advice too.