Correct radiator setup rad->block or block->rad?

My current setup is having the freshly cooled water being pumped into the water block and the water coming out of the block going into the resevoir. But I was thinking, I know that the higher the temperature of the water a radioator receives, the better it will cool it (or the delta of what cooled is bigger than lower temperature water). e.g water coming at 50C might get cooled to 35C for a delta of 15C, but water coming at 40C might get cooled to 30C for a delta of 10C. Meaning the radiator is cooling better in the latter case. So this led me to think of making the water for the intake on the water block come from the water reservoir and the water that comes out of the water block go directly to the radiator for more efficient water cooling. Any thoughts or comments on this?

I think I get the gist of what you're trying to get at.

Any way you run your loop you're only going to have so much cooling and so much heating the water. The colder the water going into your blocks the colder the blocks will be.

Any way your route the water, the coldest will always be directly after the radiator.

Let's assume your pump is in your res.

Radiator-Block-Res

That's how to get the lowest temp at your Block. If that's what you're shooting for.