If you do not change anything else and the rich amine has not fully approached equilibrium with inlet gas CO2, then the percentage of inlet CO2 absorbed will increase. However, the sweet gas CO2 concentration will also increase if no other correcting changes are implemented.
Assuming that to treat 285 MMSCFD of this gas with aMDEA to 50 ppm CO2 uses all of your available amine circulation and reboiler duty, then switching to a sweet gas spec of 100 ppm CO2 only increases your capacity to 293 MMSCFD. No appreciable gains are available from adjusting amine blend...
You can also get access to a process simulator that specializes in acid gas removal and amine sweetening. The folks at Bryan Research & Engineering know a lot about simulating processes like you describe.
I believe Sulfur Experts and Brimstone provide on-site services to analyze the streams you mention. BR&E's ProMax accurately and easily simulates amine contacting, amine regeneration, sour water stripping, SRU, and TGCU in a single model. Model predictions might be useful to you as well.