As mentioned, there is no "right" answer. A reserve fund study must be done every three years by a qualified person (usually an engineer) and must be attached to the Status Certificate. The latter is required to be supplied to a purchaser when buying the unit.
A lawyer may or may not have enough knowledge to interpret the study. But in any case, the study is based on a number of estimates. The age and remaining life of the various components of the building must be estimated. Another major estimate is the rate of return that the money in the fund will earn. In recent years, interest rates have been historically low, which reduces investment returns.
Don't rely on so-called rules of thumb. A building which is only a few years old probably will require relatively little in the reserve fund, while an older building requires more, particularly if maintenance has been neglected. (see some recent stories about a building in Rexdale where a huge backlog of deferred maintenance has built up.)
The best advice, although pretty unscientific: wander around the building and try to judge for yourself if the place appears to be well maintained. If over 20 or 25 years old, try to determine if the underground garage will need renovation soon. This is a costly item. Other big items include balconies (if any) and elevators.
The condo board of directors is required by law to put into place a specific plan to fund shortfalls. However, people don;t always do as they are supposed to, as recent experience at Panorama Court has shown. (Personally, I'd like to know how they got away with that for so long.)