Brewing classic styles partial boil conversion

[RogueGoose85]

Greetings brewers. My first post on the boards is a request for help. Figured this would be the best board to ask.

I'm brewing the dry stout from BCS, and am doing a partial boil, partial mash.

Since I am doing a partial mash, my extract has already been reduced from 5lbs to 3.6lbs, and I am adding 2lbs of American 2-row to do the mash.

Jamil states that when doing a partial boil for the recipes to do a calc for how much LME to add pre boil and post boil. Since I am now doing a partial boil and a partial mash, 1) do I still need to do the calculation to determine the amounts of LME (now, 3.6lbs) to add pre- and post-boil, and 2) do I take in consideration the fact that I'm using 2lbs 2-row for the mash?

Hope my question isn't too confusing. More or less, I want to do a BCS recipe, partial boil, partial mash - what, if anything needs to be done?

Thank you!

[spiderwrangler]

I'd just hold half of the recipe's LME back and add that at the end. So if it was calling for 5, but you are only using 3.6, leave 2.5 of that until the end of the boil. Close is fine, you don't need to be super precise, and there are a couple of thoughts on whether it even matters.