Lvl 4 synth

Where does everyone think is the best place to find purple synths? I like 645 personally, here are my stats:
1-15: 0
2-15: 0
3-30: 0
4-45: 1
5-45: 3
6-45: 4
Crystal boxes: 0
I've actually probably played 545 more than any other boss (at least since update 1.4, which is when I got my first level 4 synth) but have gotten the most synths from 645.

I would have to say 4-45, I have been very lucky there

and me lucky, that is not normal.

445 - 4
545 - 3
crystal box - 1
Forced synth - 9

Didn't add forces, but that's also 0 lol. Everyone always says 445 but I've only gotten one there :/ and the lag is terrible lol

Most of mine were from 4-20 and 3-30, got 2 from 645, 3 from crystal chests, and you know schwag 9 forced,

4 of those forced were in las week and half!
3 i did in 1 night in a 2 hour span, also then got synth 4 from crystal chest right after

Iv only seen 2 in my life and i was lucky enough to get both of them, got one from boss 4 and one from boss 6, most people seem to get them from boss 6 so i would keep trying from there, you can always force synth if your having no luck. in the time you take to actually get a level 4 synth you could probably get enough level 4 stones to synth without the sythethis stone