Hi Scott
Cracked it !
I’m going to go through my method so that you can give it a go next time.

Open the attached file so that you can refer to it as we go along.
Luckily I have GW’s book and after a bit of number crunching I confirmed that the volumes given in the recipes are End of Boil Volumes (EOBV) this is a tremendous bonus when converting a recipe and takes out a lot of guess work.
The first value I want to get right is the EOBV in cell B11, as this is a cell that has a formula in it we have to change the value by altering the Brew length figure in B5. With a bit of guessing I came to the value of 15.08L which gives you an EOBV of 19L to match the original recipe. Don’t worry if this is not the volume you want to brew we’ll come to that later.
I then changed the efficiency in cell B9 to match the original recipe efficiency figure which GW quotes as 75%. Again this is below what we can expect from our biab but we’ll come back to this.
The next thing to change is the OG to match the recipe so I changed cell B10 to 1.049
The last thing to do on this page is to change cell B13 to match your pot size. 38.3
There are other values that can be altered so as to match your equipment more closely but as this is your first brew we have no historic data. As you brew more and keep records you will be able to dial in values like your evaporation rate and trub losses so making the calculator more accurate.
You can now see that this gives you a grain bill of 4044grams not exactly the same as the recipe but this is because the calculator uses a slightly higher yield per Kg figure in its formulas and GW’s OG figure is rounded up to 49 points. It also gives you your water volumes and more importantly your approximate mash volume, this is the space all the water and grain is going to take up so ideally your boiler size needs to be big enough for this figure. (There are things you can do if you want to brew outside of the limits of your pot but I won’t cover them here.)
Now we move on to the grain bill page. I entered the grains as per the original recipe (4120g), as it’s a single grain brew I only had one set of details to enter. From this the calculator automatically scales the grain bill to suit your recipe (4044g). The bill can be entered in either weight or percentage depending on the information you have available. The percentage figure will always take presidence even if a weight value is added. On future brews with more grains just follow the recipe and input the grains in order and they will be scaled ok.
The hop bill now needs to be scaled. I entered the hop names, quantities and the AA% from the original recipe along with the time of the addition. I also entered the EOBV from the volumes page (19L) in cell E8. You’ll notice that I’ve entered 0.01 for the 0 minute addition. This is so that I could get your version to work out a scaled value, you don’t have to do this in other versions of the calc’ so it’s a bit of a work around. I then entered the AA% values for your hops in Cells J11, J12 & J13. This calculates the weight required to match the IBU’s . You’ll notice that the IBU value is high by a couple of points. This is because the calculator uses an average of the worts gravity for its calculations resulting in a more accurate figure. GW uses the OG of the recipe. The easiest way to adjust this is to reduce the boil time for the first hop addition (Bittering hops) Changing this to 60min brings the total IBU down to 38.2... close enough !
And lastly ......
I’ll leave the rest to you Scott. The recipe just needs adjusting to your efficiency and volumes. Go back to the first sheet change the End of Boil efficiency figure in Cell B9 to 79% or so. 79% is a good starting point for a first brew. Then just change the Brew length value in Cell B5 to whatever you want, the calculator will work everything out for you. Just keep an eye on the Mash volume figure in B21 so that you don’t have too much for your boiler. Max 40L !!!!
Save a copy under a different name and have a play around, you'll soon suss out how things work.

any questions just ask.
Yeasty
You do not have the required permissions to view the files attached to this post.
Why is everyone talking about
"Cheese"