Back when I used to go to a public shooting range, I'd have 15 rounds of each load (all carefully labeled and identified). I'd shoot two 5 round groups, then clean the rifle and shoot 3 foulers. That way I always felt like I was starting from the same exact place with each load. That approach also gives the barrel time to cool down and by the same amount. And like someone else said, I never did the extreme deep cleaning. I just used Shooter's Choice till I got a relatively clean patch.
Now that I have my own range and my loading gear is 40 feet away, I do 3 round groups (cleaning at regular intervals) until I find a load that looks promising. Then I'll switch to two 5 shot groups to see if the load is as good as I had hoped. The barrel cools while I'm cleaning and while I'm working up new loads.