PEG 300 question

[ippon1]

Ok I can find PEG 200 and PEG 400 but no PEG 300 what's up with that since PEG 300 is the most useful. Can I combine 200 and 400 50/50 and get a weight of 300?
Trying to make var liquid which has a weight of 306.

 

[SlimJim300]

I'm gonna be making some liquid var, too. PEG 400 will work as a substitute, just in case you can't find 300.

-Slim