If you have the stock dust caps that have a cylindrical appearance, those are very difficult to squash flat enough to clear tricky center caps. There are some that are smaller dome shaped that can be flattened a little easier, just have to be careful you don't mash them so much they rub on the castle nut. Look for them in the Dorman/HELP aisle at the auto parts; I forget the part #. They also are somewhat of a loose fit so you may need to dimple the flange edge a tiny bit (from inside-out) to help them stay attached. I know this all sounds hokey but I've had great success with this on installing wheels with really "close" center caps that otherwise would not fit.
Next up you will need spacers; you don't necessarily need 1/4" as there are some that are a bit thinner so you'll have more lug nut engagement (SAFER) .. you may have to do some hunting. IIRC the thinnest slip-on spacers I found are the crappy-looking (but useful) generic type with two lug patterns on them, and you may need to carefully enlarge the holes on the 5x5 pattern as they didn't consider 14mm studs, they appear to have been made with the old squarebody or big car 5x5 that uses smaller studs.
You can do this without cutting your spindles, which is sketchy as hell. Me; I'd pick different wheels..
Richard