Retrofitting old files with 3.6

Now that I have some time, I plan to go back and retrofit some old scores--about 40, I think--with some (but not all) of the engraving advances in 3.6. They are mostly set in Emmentaler, which I plan to keep; I have used an imported font--Cardo--for title-frame texts, lyrics, and a few other text elements; but most of the others are in Freeserif, which I'd like to change to Edwin. I figured I could create a master style template file, and then apply it to each score. But when I tried, it also changed things like margins, etc., which vastly altered layout and spacing (I would assume these fall under the "page settings" menu, not "style.") I've worked very hard to create good layouts, and I'd rather not have to adjust them any more than neccessary. Suggestions? Thanx-- WF