Cannot change disk mapping when auto installing debian - installation

Question

I have 2 types of industrial computers, and I want to install debian automatically :
- 1 PC with ssd mapped on sda
- 1 PC with ssd mapped on sdb
I have a preseeded debian iso on usb drive for installations.
So, the problem is : when I configure my preseed file, I need to set what is the target disk (sda or sdb), so it cannot work for both, and I didn't find any solution to set "the biggest disk will be the target" (my ssd is 64 GB, my usb drive is 4 GB) or something like this.
I have tried to include udev rules in iso image to always map the ssd on sda, but it does not take in account...
udev rules included (000-install.rules), I have tried those 2 :
KERNEL=="sda*",ENV{ID_FS_LABEL}=="CDROM",NAME="sdb%n"
KERNEL=="sdb*",ENV{ID_FS_LABEL}!="CDROM",NAME="sda%n"
and :
KERNEL=="sda",ENV{DEVTYPE}=="disk",ENV{ID_FS_LABEL}=="CDROM",NAME="sdb"
KERNEL=="sdb",ENV{DEVTYPE}=="disk",ENV{ID_FS_LABEL}!="CDROM",NAME="sda"
My preseed conf file :
#### Contents of the preconfiguration file
### Localization
# Preseeding only locale sets language, country and locale.
# Debian 9 & 10
d-i debian-installer/locale string fr_FR
d-i partman-auto/disk string /dev/sda
d-i partman-auto/method string regular
d-i partman-lvm/device_remove_lvm boolean true
d-i partman-md/device_remove_md boolean true
d-i partman-auto/choose_recipe select multi
d-i partman-partitioning/confirm_write_new_label boolean true
d-i partman/choose_partition select finish
d-i partman/confirm boolean true
d-i partman/confirm_nooverwrite boolean true
## Controlling how partitions are mounted
# The default is to mount by UUID, but you can also choose "traditional" to
# use traditional device names, or "label" to try filesystem labels before
# falling back to UUIDs.
d-i partman/mount_style select label
Result (the file above works when ssd is mapped as sda, but not when it is sdb): installer tell me there is no enough space on sda (so on usb drive...)

Answer 1

First of all i want to tell you "udev was created to respond to hotplug type of events"
for example if you want to trigger a specific script when a specific device is plugged you can use this daemon.
another example of using this daemon is when you want to refuse a specific device to insert to your target machine.
in the other hand the biggest problem for using this approach to solve your issue is this:
The times when udevd is active are:
1: at startup, it parses all the config files and rule files and
builds a rules database in memory.
2: When an event happens, it checks its rule database and performs the
appropriate actions.
please look at this reference
The system initialization
so when codes for partitioning of your device is executed by debien-installer your root filesystem already mounted. therefore you cant unmount a root deivce that was already mounted and simply mount it to another device.
if you want to find the biggest device I suggest you looking at "debian-installer" that can execute udeb packages ( this type of packages can only execute in debian-installer). if you can create a udeb package that can execute a script in which it can detect which disk must be mounted in root system, before mounting root system by partman package you can solve your problem.
look at this reference below in which you can see order of udeb package installation existed in debian installer.
https://d-i.debian.org/doc/internals/apa.html