Returning to Redstone 1 from Redstone 2 without a clean install?

Ok, thanks for the experiment @Cerberus.
@Placebo -
You have two options.
A.
1. Create a disk image of your Windows partition and anything else related as far as program installation is concerned (if any).
2. Buy a copy of the relevant Laplink program
3. Install the Windows version (same 'bitness') you want to use.
4. Run the Laplink program to 'reinstall' your programs and apply settings using the disk image.
(I've no experience of how it handles universal apps, but it's 96% or so accurate with desktop progs)

B.
You've guessed- conventional clean install.

The decision is yours: spend ££s and save time and enjoy the convenience - valid if you have a LOT installed- or DIY with a clean install.

Placebo said:

Aha never heard of Laplink I'll check it out thanks :)

There are several programs eg laplink pcmover (i think), zinstall, easeus pctrans that will backup programs but they are not that cheap and not that reliable. Frankly, I would clean install and update manually.

I've used Laplink several times, and been very impressed- and that's with a LOT of programs. Thus for me the time saving was significant. just very a few progs - a small %ge- it didn't work completely for, a minor inconvenience. It even happened to move the license key for a good number. I wouldn't use it to move an Office type program, and certainly not any form of AV or firewall.

It would be worth checking with Laplink first about going backwards with win 10 builds.
Zinstall is more expensive (not tried it) and Easeus PCTrans is more restricted than Laplink, which has a longer history.

I did a Laplink transfer on a PC running over 100 applications last year to move it from 8.1 to 10 and it worked reasonably well. I did develop stability issues longer term and ended up having to clean install and rebuild the app environment about 4 months afterward. But if you're in a hurry and don't mind spending the $20 (US price, I think) to get a one-time-use license, it's a definite time saver.
HTH,
--Ed--