Only need a fair advantage for something like this;
1. Go to a boxing gym regularly while training for your contest.
2. Be absolute in your diet / training
3. Take time off work 3-4 weeks before fight to "live the life" before tapering down
tbh, if your opponent is doing all the above fair play - but from guys I've known do this type of thing, they feel going to the mandatory training session is an achievement.
Unfairly... if you got the resources, had planned it months in advance and happy to do it (??!!!? if are, should get into non-contact sports) you should definitely gone with testosterone, could went further with HGH and DHEA. To make weight; thyroid hormones and HCG.