Alas I'm at work and don't have BeerTools in front of me, but here's some ideas I have:
"mashed at a low temperature to increase the amount of fermentable sugars"
To me, this would mean ~148F.
For OG, 12.5% is pretty ridiculous. And being so high, it's hard to get FG down to really low levels. If we pick FG at 1.016 (which is pretty low for a IIPA, especially one this big), that would mean OG has to be 1.100!
Otherwise, malts are generally listed from higher to lower amounts. Obviously you'll have mostly 2-row, but have more Crystal 20L than Special B than Crystal 120L. Matching color will reign in the Special B and 120L amounts.
If you have some brewing software, just play around with numbers until you hit something that looks reasonable and comparable.
Hope this helps!