I have only done four pannier touring, not two.
No two people do the same, there is no right or wrong way.
I have a kickstand on two of my touring bikes, and on those the one pannier I can remove without upsetting the bike balance on kickstand is the front right. So, the front right is where my tent is because when I get to a campsite, the first thing I want to do is get the tent up.
Tent is usually wet from dew or condensation or both when I pack it in the morning, so I do not want anything in the front right pannier besides the tent unless it is something that I do not mind getting wet. Sandals, maybe my air mattress that dries out quickly often go in that pannier too.
Left front, most trips that has cooking gear, stove fuel, food that will also fit in there. I try to get both front panniers to be about the same weight.
I use Ortlieb Frontloader panniers up front, they each have a strap over the top. I strap my rain gear on top of front panniers where it is handy and I can also see it in case it starts to work loose.
Rear panniers, everything else. Dense stuff in bottom, like tools and if I carry a spare tire, this is also in the bottom. Canned food near the bottom. Lightest stuff on top. I try to organize by knowing what is in each of the rear, but each trip I fall into a routine that varies from previous trips.
Sleeping bag is in a compression stuff sack. That goes on top inside of one rear pannier. Might also have a down vest in same sack. Some trips have used a second compression sack for other clothing, that is on top in other rear pannier. If my compression sack was not too full and i have extra room next to it in the pannier, I will shove something in there.
Three photos below, first is compression sack next to a pannier, second is compression sack inside pannier, and third is the pannier closed.
I usually have another bag on top of the rear panniers, often that has food in it. That bag might be nearly full or might be almost empty. And some odd shaped light stuff like hiking shoes or sneakers are often in that bag because the do not pack well. I have to get the two rear panniers packed almost exactly the same volume so the rear bag on top is not trying to slide off to one side. Photo below.
Handlebar bag. That has my valuables and stuff I may want quick access to (sun screen, a small multi-tool, chain lube, etc.). That goes in stores and restaurants with me. And I usually have all my electronics in that bag too. Heaviest stuff in that bag to the rear closest to the steering axis, least dense stuff in front.
Some trips where I did not need as many warm clothes or did not have to carry as many days of food, I used a much smaller bag on top of the rear panniers, like below. On the trip where I took the photo below, the last few days I did not have any bag on top of the rear panniers, that food had all been eaten and the drybag was folded up and stowed elsewhere.
I think most people put the sleeping bag or tent on top of the rear rack, that works for them. But I like the bag on top in back to be able to fluctuate in volume in case I need to carry extra food on part of a trip, or if I have food that I do not want to crush, like baked goods or eggs, etc.