sorry the test is proprietary to Analysts Inc. They will not sell you the solvents.
Two other labs we know of who may be able to help are Insight Laboratory,(http:www.testoil.com) and Focus laboratories LTD. (http://www.focuslab.co.th)
use petroleum ether or n hexane available at most lab supply houses. Mix with oil, 25 ml each, pull a vac through a .45 micron filter patch. Insolubles will drop out on the patch.
zmgh, we at Fluitec sell the complete varnish testing kit for those interested in performing this test on site. Please feel free to contact me or visit our web site for further information.