For full details on "Don't lose 25% of Experience when Farming in RAID" see that blog post - here I am just giving yet another example of implementing that in practice.
I made another 6 star (Armiger) and I had also summoned Versulf from the fusion fragments who I am planning to use in an Ally Protect Clan Boss Team. Among various combinations I am planning, two of them also include using Aothar as poisoner, instead of the Frozen Banshee, because she does not always get the chance to put her Poison Sensitivity.
So I took my new level 1 Armiger (with +8 / +12 gears) and I put on Versulf +8 gear (items I will upgrade later during Artifact Upgrade event) and I kept Aothar without any equipment.
Added 1 food champion and sent them to farm Hard 12-3. Even at such low level and gear they won 100% of the time. Despite not having any healing, Armiger and Versulf survived to the end and usually ended with approximately half the health.
This allowed me to get 100% of the Experience and not lose 25% of Experience due to a maxed out Farmer!
With some more levels and few upgrades I am sure they can start doing Brutal 12-3, but I may also stay in Hard to get more rewards which I need currently.
Here are some supporting pictures:
The Team (position view)
The Team (battle view)
Versulf's equipment
Armiger's equipment
And as mentioned I did not give any equipment to Aothar and the Food Champion (naturally).
Update: around level 40-45 I tried Brutal 12-3 and although Versulf died on wave 3 with his +8 gear, Armiger managed to finish the fight. I still think Hard 12-3 is better and safer until Artifact event when I can upgrade their gear.