I recently got these two strand twists, but I only have around 50 and I’m aiming to have somewhere around 100 locs. What’s the best method to hit that goal? Should I wait a couple weeks before twisting out and letting that loc or should take these out and just get a new set of two strands?

You should get a new set if you want the parting to make sense.
Depends on how big you want your locs to be, these will defo be quick thick ones
Naw I don’t think you should personally
I’d split them as they’ll be very thick locs. Just depends on your personal choice - thick or medium