Shininess (and gender, nature and ability) is set by the PID RNG. If you copy the long version of the seed from Time Finder into the main window, selecting PIDRNG from the dropdown (or 5th Gen Natures depedning on your version of RNGReporter), as well as choosing the correct encounter type, synchroniser (if you're using one) and so on, you can hit generate and see what nature each frame will be. After entering your ID and SID you can tick the shinies only box, and it will show you which frames will be shiny. You need to then work out which PID RNG frame you're starting on, and advance it to the correct frame. The easiest way to advance is probably by using a Chatot with a prerecorded Chatter attack; every time you move over it in the summary, it will chatter and the PID RNG will advance by one frame. To work out your starting frame, (easiest not to use a syncher for this calibration) get to the right IV seed/frame and catch your Pokémon. Note the nature, gender, ability. Then repeat, bbut do one chatter first. Then repeat, but with two chatters. Once you've got enough data you can look down the list and see where you're starting.