I've got a spare set of 40cm wide RB-018.

Man, guys on LAfixed and velospace sell rb-021's for like $20. Keep your drops, don't cut them, buy a set of real bullhorns and a new stem. This way, you won't have to go back and buy a new set of drops and tape when you decide you want to go back in 6 weeks. Having handlebars mated with their own stems makes bar swaps so easy and convenient.