Time Machine Backup: New Partitioning and a Restore I have a MacBook Pro mid 2009 with a 250 GB SSD split in 2 partitions: (1) OS X El Capitan (200 GB) and (2) Debian Linux (20 GB). 

Willing to give more space to Debian, I will wipe the SSD and reinstall everything from scratch. To put things into order, I thought about utilizing Time Machine for backups and restores. 

If after wiping the disk the created macOS partition is smaller than the previous one, will I be able to have a successful restore (assume that the real old data fits in the new partition)?
Time Machine is a file-level backup so the size of your partition will not be taken in to account.

In fact a block-level backup also would not be an issue, only taking a disk image would be problematic as a disk image includes the file system whereas backups do not.