I don't know how much a heavier bullet would increase pressure with a smokeless load so I would stay away from that myself. My guess is that increasing the bullet weight by 10% would increase the pressure by more than 10%. Higher pressure in itself will cause the powder to burn faster. The rule of thumb that says pressure is proportional to the fourth power of the powder charge applies to any powder that is working in it's normal pressure range. Any given powder will work at its best in a certain pressure range. For example, a shot gun powder will burn smoothly in the 10000 to 15000 cup range while most slow rifle powders will not burn smoothly at such a low pressure. But it is only a rule of thumb, your milage may vary.

There are pressure measuring systems available to the individual experimenter but they have the drawback that they measure pressure relative to a given factory load rather than giving you the pressure itself. In other words you can say your handload runs 1.07 times the pressure of a given factory load but you can't say what the pressure actually is. A true pressure measurement requires a test set up that's beyond the average guy's means.