Intentional caramelization technique question

[Moody_Copperpot]

I just read a bit about the Intentional caramelization technique, in which up to a gallon of first runnings are taken and then boiled down by say 75%. I am doing a mild/session ale type brew tomorrow, and I've got the itch to give this a shot. Here are my questions for those who've done this:
1) I try to keep my mash and sparge volumes as even as possible. Would I up the entire water to grain ratio to allow for that gallon to be boiled down? Or would I just increase my mash water volume to account for that gallon I'm taking out and boiling down, so I'd still end with the same amount in the kettle?
2) when is this wort reduction added to the rest? I assume it just gets added to the kettle for the duration of the boil.

 

[JonK331]

1) I'd keep the grist to water ratio the same and use 3/4 gallon more sparge water.
2) Reduce the first gallon by 75% and then add the rest of the wort.

 

[Moody_Copperpot]

That makes sense, I think I'll do that.

 

[LakewoodHomeBrew]

1.) +1 same ratio and extra 3/4 gal.
2.) combine after the boil.

 

[Moody_Copperpot]

I did it last weekend and I worked like a charm! For optimal efficiency I make my strike and sparge water volumes as close to equal as i can. I just upped my batch size to 6.75 in my software to get the proper ratio, then changed it back to 6 for my target og. I collected my gallon, boiled it down over 90-120 min and I ended with 86% efficiency!