i did a quick search for some guidelines, so ill copy/paste what ive found. taken from this site:
http://www.heroinhelper.com/sick/met...x_part_2.shtml
Starting Dose:
The first thing the addict must decide is at what methadone dose to start the detox. A good rule of thumb is that if an addict is doing a gram of heroin per day, he should start his detox at about 30 mg per day. The relationship between former heroin use and beginning methadone dose should be linear. The table below shows this. The first column is the amount of heroin the addict was using each day before he started the detox. The second column is the amount of methadone the addict should take the first day of his detox.
heroin use / methadone dose conversion:
0.25 g (daily heroin use)= 10 mg (methadone dose)
0.50 g (daily heroin use)= 15 mg (methadone dose)
0.75 g (daily heroin use)= 22mg (methadone dose)
1.00 g (daily heroin use)= 30mg (methadone dose)
1.50 g (daily heroin use)= 45mg (methadone dose)
2.00 g (daily heroin use)= 60mg (methadone dose)
3.00 g (daily heroin use) = 90 mg (methadone dose)
Course of the Detox:
There are basically two ways to handle the methadone dose during the course of the detox. The first is simply to use the same dose each day. Although this is the easiest way to divide up and administer the methadone, it has a few problems. The first is that the same dose every day will not translate into the same amount in the body everyday. This can be seen in the graph below where a dose of 20 mg is given each day. The other problem is that the body will not respond to the abrupt change in dosage and the withdrawing addict will be less comfortable.
The other option is to decrease the methadone dose each day. There are various ways to do this but each is just about as good as the other. In this case, it is best to simply have the dose decrease the same amount each day. So an addict would decrease the dose each day by the starting dose divided by the length of the detox in days. So if the starting dose is 35 mg and the length of the detox is 7 days, the dose would be decreased by 35 ÷ 7 = 5. Thus the dose each day would be: 35, 30, 25, 20, 15, 10, and 5.
Length of the Detox:
Between five and ten days. It is best not to go over seven days, in fact.
Conclusion:
Detoxing alone has many advantages. The only real drawback is that doing so is illegal. This is an important drawback, however. While it is true that cops and courts are more likely to go lightly on an addict who is trying to get clean, possession of methadone without a prescription is just as illegal as possession of heroin and can send one to jail for years. Any person going outside the clinics to detox should be very careful and aware of potential hazards.
Another important issue to keep in mind with methadone is that it is dangerous. Children are often attracted to methadone because it is normally distributed as a brightly colored liquid. Each year, children OD on methadone because they mistake it for something like Kool-AidTM. Keep methadone away from kids! And the addict must not forget to be careful when dosing himself.