Rubber Door Bumpers - Help

So I just got my rubber bumper kit, which included the door bumpers. The bumpers included in the kit are longer and much more meaty than the ones in my '68 vert. I bought them on ebay and the seller said I can cut the length down so they'll fit in the hole where they go and they should be fine. Here are two pics that show the difference in size. Can I purchase the correct bumpers (there are a total of 4) for my doors, and if so where......or should I just go ahead and cut the ones pictured so they fit?