In regards to Disk Tools--the name Disk Tools only came about with System 7. The disk with Apple HD SC Setup was called System Tools in System 6 and earlier if you're using 800K disks (which I assume you'd want--not sure if your SE has a SuperDrive or not) and System Startup if you're using 1.4MB disks.
If you're using Apple's downloads, use the four-part System 6.0.8 to get an 800K System Tools floppy. It's probably Part 1 of the four part download (not 100% sure since I use the original floppies in emergencies). If you do have a 1.4MB drive, use either the 6.0.8 System Startup disk or the Disk Tools floppy from the 7.0.1 set. I find either all of these easier than using Apple's 7.5.3 download (honestly, you're better with that version on CD-ROM unless you have a lot of floppies and a lot of patience).
Another option is to track down Silverlining or Hard Disk Toolkit. These are commercial products--you have to acquire a physical disk and license to use them--but are pretty advanced as far as formatting goes. I've used Silverlining and know it is very easy to set interleave with it.
If you're using Apple's downloads, use the four-part System 6.0.8 to get an 800K System Tools floppy. It's probably Part 1 of the four part download (not 100% sure since I use the original floppies in emergencies). If you do have a 1.4MB drive, use either the 6.0.8 System Startup disk or the Disk Tools floppy from the 7.0.1 set. I find either all of these easier than using Apple's 7.5.3 download (honestly, you're better with that version on CD-ROM unless you have a lot of floppies and a lot of patience).
Another option is to track down Silverlining or Hard Disk Toolkit. These are commercial products--you have to acquire a physical disk and license to use them--but are pretty advanced as far as formatting goes. I've used Silverlining and know it is very easy to set interleave with it.