The other trick to try is to see how far forward you can move the cowl. If the cowl isn't predrilled or fixed by a cowl ring and there's enough fiberglass to make it work, you can slide your engine forward until you have proper clearances for the engine box, then move the cowl to the point where it aligns properly with the drive washer and/or spinner. My Phoenix Edge 540 worked out like this; I ended up sliding the cowl forward about 10 mm past where the specs were. There was plenty of material for the attachment screws, and it balanced out just fine.