IPA with Hop substitutions

Hey all,
I am brewing Jamil's American IPA from his book "Brewing Classic Styles".
The recipe calls for Horizon hops as the bittering hop but all I have on hand for bittering are:
1/2 ounce Warrior
3oz Chinook
2oz Columbus
I am thinking about doing the 1/2 ounce Warrior along with 1/4 Chinook.
I know the two hop styles are very different but its the only way I can use the 1/2 oz of Warrior in the recipe.
Good Idea?
Also "Designing Great Beers says to mash @ 1 quart per pound for PAle ales and IPA's. I normally brew with 1.25 or 1.3 quarts per pound.
Should I go with the thick mash? I want this beer to be dry so I am using a 90 minute mash with a temp of 149F.
Thanks in advance! :rockin:

Jamil's IPA

A ProMash Recipe Report

Recipe Specifics
----------------

Batch Size (Gal): 5.25 Wort Size (Gal): 5.25
Total Grain (Lbs): 15.25
Anticipated OG: 1.073 Plato: 17.63
Anticipated SRM: 8.2
Anticipated IBU: 62.4
Brewhouse Efficiency: 70 %
Wort Boil Time: 60 Minutes

Grain/Extract/Sugar
% Amount Name Origin Potential SRM
-----------------------------------------------------------------------------
83.6 12.75 lbs. Pale Malt(2-row) America 1.036 2
6.6 1.00 lbs. Munich Malt(light) America 1.033 10
6.6 1.00 lbs. Crystal 20L America 1.035 20
1.6 0.25 lbs. Crystal 40L America 1.034 40
1.6 0.25 lbs. Cara-Pils Dextrine Malt 1.033
Hops
Amount Name Form Alpha IBU Boil Time
-----------------------------------------------------------------------------
0.25 oz. Chinook Pellet 11.50 12.1 60 min.
0.50 oz. Warrior Pellet 16.40 34.6 60 min.
1.00 oz. Centennial Pellet 8.60 7.3 10 min.
1.00 oz. Simcoe Pellet 12.00 8.4 5 min.
0.25 oz. Amarillo Gold Pellet 8.90 0.0 0 min.

Yeast
-----
White Labs WLP001 California Ale

Mash Schedule
-------------
Mash Type: Single Step
Grain Lbs: 15.25
Water Qts: 20.25 - Before Additional Infusions
Water Gal: 5.06 - Before Additional Infusions
Qts Water Per Lbs Grain: 1.33 - Before Additional Infusions

Saccharification Rest Temp : 149 Time: 90
Mash-out Rest Temp : 0 Time: 0
Sparge Temp : 185 Time: 0


Total Mash Volume Gal: 6.28 - Dough-In Infusion Only

I've actually heard Jamil say that you don't need to be to picky about bittering hops, which makes sense. Just use what you've got that will equal the alpha % the recipe calls for.

You're fine with the substitution. And your mash should produce a highly fermentable wort.

Thanks guys.
I am going ahead with the recipe as is.
Dustin