I've bought an FKD 13x18 camera and it's come with 5x7 film - lots of it! Am I likely to experience any issues? Are the wooden film holders OK to use with 5x7 film or will I need to adapt the holders (how should I do this)? Do all FKD film holders accept 5x7 film? If not, is there anywhere I can buy 13x18 film anymore? Thanks for your help H