Talking about RAW here isn’t particularly useful
As an Unearthed Arcana variant, the gestalt rules are mostly just suggestions and ideas – fairly fleshed out, for the most part, but it’s a mistake to think of them as really complete rules.
They don’t cover this situation directly. Taken literally, you would simply get the greater number of power points between the two classes, but that is quite dissatisfying; you lose a ton of power points compared to the spells slots of a gestalt spellcaster//spellcaster.
The bonus power points for high Int and Cha would combine, though. So the answer there is 46 + ½ML(Int+Cha) power points per day.
Unfortunately, it is very difficult to identify “best practices”
Simply letting the character combine both power pool counts into one results in a potentially huge number of power points, and also provides a flexibility greatly exceeding what spellcasters receive. Thus, 46 + ½ML×Int + 46 + ½ML×Cha power points per day.
On the other hand, strictly segregating power points for each side of the gestalt is quite out of keeping with how psionics works in general; after all, multiclass manifesters combine all their classes’ power points. But going this route does eliminate most of the balance headaches, simply giving the two sides 46 + ½ML×Int power points per day for the psion side and 46 + ½ML×Cha power points per day for the wilder side, and the power points cannot be spent to pay for the other class’s powers.
Personally, I prefer the former; it may be a huge number of power points, but then manifesters are a little worse off than spellcasters to begin with, and a gestalt spellcaster//spellcaster isn’t really that great an option to begin with. By combining power points, the gestalt manifester//manifester actually synergizes his or her two sides quite well, and the two sides are almost-seamlessly combined into simply knowing a lot more powers. That’s pretty solid.