hi 

The described PEG should normally work quite well with that essential oil Combinations. 

The first question would be how much solubilizer did you trie of the ones you have used already? 

Concentration is a big part of solubilization. I would estimate around 1 - 4 % of Solubilizer depending on the Essential oil Combination.

Second, how did you incorporate the Essential oils in the Product? just added all ingredients and Stierd or did you follow another path. 

For Solubilisation, it is very important sometimes to pre-solubilize the Essential oil within the Solubilizer without any water and then add it to the rest of the Formulation. 

hope that helps a little if you can give some more information about the used levels of the solubilizer and how you incorporated it in the Formulation that can give some more hint and help. 

Tobias