PGNEXUS

I wouldn't risk it since such sites are against Pokemon Go's Terms of Service, it's up to you however if you think the risk is worth it.

Try this after catching, for example 50 pokemon:
1) sort by recent
2) open the firt of these pokemon you caught (the older)
3) menu->appraise->one tap
4) with the oher hand do 5 taps (5 fingers o 3 fingers x2)
5) if the pokemon is 82% or more make it favorite
6) tap on the left of the pokemon page to switch to the next

Repeat steps form 3 to 6 until you reach the last pokemon.
After that you can select all these 50 pokemon (except the ones with the star) and transfer them all.
You'll save a lot of time compared to the old method.

If it were safe id love to use it, but its not. As a result I dont check IVs on everything. I wish I could but the amount of time involved checking IVs and flipping thru 1k mons all the time isnt worth the effort. Id rather be catching and fighting then organizing and checking.