What is the best way to determine the volume on the backup media under the time mashine and how does it work?

Question

Backup

The volume of a regular hard disk (fusion drive) on imac = 1000 GB.
A "bare" system is installed on it and everything that was by default, finder shows that about 23 GB is currently occupied.
It is supposed to use a computer for the work of the designer.
The main software in the work that will be used and installed is:
- Adobe CC last version + update package
- Sketch + Plugins
- Axure RP Pro
- some virtual machine with win7 ... 10, and on it Corel Draw (last version )
- office applications for working with Microsoft
- Blender
Well, let's say with a margin the entire collection of integrated software will take roughly 100 GB.
That is, it will be a tenth of the useful volume of a regular hard drive in the system.
Let's take a reserve of 400 GB of user data for the future, which will eventually amount to 50% of the total volume.
How much disk space should be allocated for the time mashine if I backup manually, not automatically, and not very often, at least once a week or even once a month?
I read in blogs that Apple recommends backing up a disk with a capacity of at least twice as much as a regular working (system) one in a computer.
But there is no need to save a long history of backups, and you don’t want to do it too often.
Which one is better and more optimal, do you still recommend allocating the amount of backup media for the time mashine?
Do I understand correctly that if the system + user data and all information add up to 100GB, then the time mashine will be able to backup about 10 backups on a 1000GB backup disk?
Moreover, is this true: with each backup copying transaction, the volume of the backup disk is "gripped" by the amount of the backed up data?
Or does the internal mechanism of the time mashine still somehow archive, compress, check versioning?
After all, source code version control systems do not seem to make a full backup of the entire branch of source files, but make up a tree of changes and replace only some, thereby also saving the amount of backup? Or am I a little wrong?
I will be very glad to listen to experts in data backup, system recovery and organization of network storages. Thank you!

Answer 1

In fact, a terabyte is enough for you. Even if you fill the aimak disk by 2/3, there will be enough space to write changes. I have two macbooks with 120 gigabytes of disks backed up on a 500 gigabyte disk, in total less than 200 gigabytes are occupied, given that they are backed up regularly and for a long time.