In fiction, there are many characters of Large Size. When it comes to tiering them their size alone can be an indicator of their statistics. This page explains which statistics can and can't be calculated from size alone.
The physical attack potency, and with it the durability, can be estimated from the size of a character alone.
That follows a simple conservative estimation: Any character can at least just fall unto someone. In other words, their potential energy can be used to attack. The only prerequisite to this method is that the character should be at least Type 0 Size on the Large Size scale.
In order to perform the calculation one will need the mass of the character and its center of mass.
The center of mass of a human-shaped character is about 10 cm below the navel, albeit this varies from individual to individual. Generally one can estimate that it is around 50% of the body height up.
In order to find the mass of the character upscaling methods are helpful. If the character is x-times larger than its normal-sized counterpart, and made of roughly the same materials, then its mass would be about x^3-times larger.
With this information, the energy can be calculated via the usual GPE methods.
Except for very large characters that is simply "Potential energy = mass*9.81*height of center of gravity". Mass should be in kilogram and height in meter. The result is in joule.
An alternative method to calculate Attack Potency from size is from Kinetic Energy. There one takes the mass of the character and uses its running speed to get Kinetic Energy via "Kinetic Energy = 0.5*Mass*(Running speed)^2". Here mass should be in kilogram and running speed in meter per second. The result is in joule.
The best practice is to measure the speed directly from the source material. Should that not be possible, but it is known that the character moves relative to its size as fast or faster than its normal-sized counterpart, upscaled speed can be used. To confirm that they are that fast, it must be clear that they, for instance, take steps within the same timeframe or less than a normal human would. If that is the case, then their speed should be x-times higher than that of their normal-sized counterpart, if they are x-times larger.
Lifting Strength should not be calculated from size. While characters have to lift more bodyweight, lifting strength is the weight they can lift in addition to that. There is no way of telling how much more that is.
As mentioned in the AP section speed can under circumstances be taken from size. An x-times larger character should also be x-times faster. However, strict confirmation is necessary.