Sure, it WOULD be nice, but I don't know how. The "don't know" refers to the case 16MB block size, my tape supports only 16MB - 1 byte (according to st report). Is there a way to test various block sizes with CDs / hard-disks / ZIP / scanners? Would something with sg_dd work? Looks like it must be only sector size. Can I low-level format a disk with 16M sector?:-)
Another possibility is to limit the block size at 8MB - I can test that.