Are the caps too big or too small? If you have a wing capper, look under the bottom of it where the metal wings are. You'll see some numbers that say 26 and 29. There's a slot on the back of them where you can prize them out and flip them around. The 26 is the US size, the 29 is the EURO size.
That said, the bench capper is probably your best bet. I should probably get one for my Martinelli and Red Stripe bottles since my capper hates them.