Suggestion for use of Penetrol with Spar Varnish and Miniwax Cherry Stain?

<p>I am Carving a Maple Tree, creating an Abstract Sculpture.&nbsp; I heard that Penetrol enhances the use of Spar Varnish.&nbsp; I was also wondering if it works with Minwax Cherry Stain (I want to get a darker Cherry Stain to the Maple Wood.</p> <p>What ratio of Penetrol to Varnish should I use. &nbsp;</p>