We are doing our best to keep all sabers with 1" blades. Some will have shallow blade holder depths, others won't. Since Rebellion sabers are not being offered with blades (to keep costs to a minimum, especially where shipping is concerned), it is assumed most people have, or can get, a 1" blade pretty easily and inexpensively.
As far as internal sizes, it depens on the saber. The KOTOR has 1 1/8" id. We are trying to keep as many sabers as we can with at least a 1" bore. Again, some designs have thin chokes so there will be some sabers with internal 'choked' sections between the blade and optic/LED setup.