This task looks unsuitable for a site like that since these are technical papers with mathematics, one has to know enough LaTeX to be able to reproduce (arbitrary) mathematics by just reading it (N.B. tools like detexify help).
Also, a single mistake (like ij instead of {ij}) can change the meaning dramatically, and I would think that a random person on freelancer would care less about getting it right, and more about getting it looking like it's right (whereas someone recruited through LW is more likely to actually care about SI beyond being a source of money).
You're right, outsourcing this would be a bad idea.
The Singularity Institute needs to hire 1-2 people who are fluent in LaTeX to help us transform past and future SI publications from looking like this to looking like this.
As with the remote researcher positions, pay is hourly and starts at $14/hr but that will rise if the product is good. You must be available to work at least 20 hrs/week to be considered.
Perks:
If you're interested, contact luke@intelligence.org and describe past LaTeX work you've done, with attached PDF examples.