My friend has a disease for many years, that I identified (by TCM patterns and symptoms) as Pointed Condyloma. There is a nice protocol of treatment, but it has 4 formulas. It is rather too much to take at once, isn't it? 2 formulas are for tonifying qi and yin, and two for purging dampness and damp-heat. So maybe first administer purging formulas for 1 month, then tonifying ones? The patient's strength is moderate. Or just take everything at half dosage, at once?
You need to practice how you are comfortable and with proper pattern differentiation. It is not uncommon for an herbalist to use 2-4 formulas combined all at once. In fact, this is quite commonly done in Taiwan. But it is of the utmost importance that the practitioner have a good understanding of the patient and what they are trying to accomplish. I frequently use multiple formulas in combination and I almost never increase the dosage above a normal dose.
Pulse diagnosis is often the big dictator as to what needs to be used and in what quantities.
In my personal expirience I have found it best to create a custom formula adressing the specific paterns and symptomology. Some times when you use multiple patent formulas, you end up with so many herbs, the potentcy of each individual herb is diminished. Many individual herbs fulfill multiple roles. Find one that fits your friends patterns most closely and make that the king herb in the formula, then find supporting herbs to create something prefectly suited to your friends situation. Sometimes I'll use a classical formula as a starting point and then modify as I see fit for the specific needs of my client. This not only makes it easier on your friend, by not making him take several seperate doses, but it ensures that the formula is addressing only that which needs to be adressed. Good Luck!
I'm too inexperienced to make formulas. The protocol I found is perfect and addresses issues that I didn't even notice at my friend at first, for example that there is both damp heat and turbid dampness.
The trick with combining formulas is truly knowing exactly how the formulas work. You don't necessarily think of them as a bunch of individual herbs, but as their collective action. So when you add 30% of this formula, 30% of this, 20% of that, 20% of that, it is almost like using 4 different herbs rather than 50.
If that formula you found is right for your patient, then great! Use the indicated dosage.
I agree with Sheri that if combination is done improperly it could affect the potency of the formula. However, when done well, formulas even with 60-70 herbs perform extremely well, even at low doses like 6 grams per day. The trick is finding someone who knows how to do this very and study with them. The guy I study with will sometimes use 1-2 herbs alone, and other times use multiple formulas comprising dozens of individual herbs.