Hello all. I plan on brewing the following beer this weekend, and the local shop doesn't have Horizon hops. What would you recommend that I replace it with and at what aa%? 
Also, I'm making two changes:
1. I plan on pitching this onto a cake of WLP400 from a previous wit.
2. I'm not adding the honey.
Thanks for the help!
Steve's Imperial Witbier
A ProMash Recipe Report
Recipe Specifics
----------------
Batch Size (Gal): 5.00 Wort Size (Gal): 5.00
Total Grain (Lbs): 24.00
Anticipated OG: 1.116 Plato: 27.18
Anticipated SRM: 11.0
Anticipated IBU: 50.2
Brewhouse Efficiency: 55 %
Wort Boil Time: 90 Minutes
Grain/Extract/Sugar
% Amount Name Origin Potential SRM
--------------------------------------------------------------------------
41.7 10.00 lbs. Wheat Malt America 1.038 2
25.0 6.00 lbs. Maris Otter England 1.037 3
16.7 4.00 lbs. Honey 1.042 0
8.3 2.00 lbs. Aromatic Malt Belgium 1.036 19
8.3 2.00 lbs. Munich Malt Germany 1.037 8
Potential represented as SG per pound per gallon.
Hops
Amount Name Form Alpha IBU Boil Time
--------------------------------------------------------------------------
1.00 oz. Horizon Pellet 13.00 48.2 60 min.
0.50 oz. Hallertauer Mittelfruh Whole 4.50 2.0 15 min.
Extras
Amount Name Type Time
--------------------------------------------------------------------------
0.50 Oz Bitter Orange Peel Spice 10 Min.(boil)
0.75 Oz Corriander Seed Spice 10 Min.(boil)
0.50 Oz Bitter Orange Peel Spice 2 Min.(boil)
0.75 Oz Corriander Seed Spice 2 Min.(boil)
Yeast
-----
WYeast 3864
Mash Schedule
-------------
Mash Type: Single Step
Grain Lbs: 20.00
Water Qts: 23.00 - Before Additional Infusions
Water Gal: 5.75 - Before Additional Infusions
Qts Water Per Lbs Grain: 1.15 - Before Additional Infusions
Saccharification Rest Temp : 150 Time: 90
Mash-out Rest Temp : 168 Time: 20
Sparge Temp : 170 Time: 0
Total Mash Volume Gal: 7.35 - Dough-In Infusion Only
Also, I'm making two changes:1. I plan on pitching this onto a cake of WLP400 from a previous wit.
2. I'm not adding the honey.
Thanks for the help!
Steve's Imperial Witbier
A ProMash Recipe Report
Recipe Specifics
----------------
Batch Size (Gal): 5.00 Wort Size (Gal): 5.00
Total Grain (Lbs): 24.00
Anticipated OG: 1.116 Plato: 27.18
Anticipated SRM: 11.0
Anticipated IBU: 50.2
Brewhouse Efficiency: 55 %
Wort Boil Time: 90 Minutes
Grain/Extract/Sugar
% Amount Name Origin Potential SRM
--------------------------------------------------------------------------
41.7 10.00 lbs. Wheat Malt America 1.038 2
25.0 6.00 lbs. Maris Otter England 1.037 3
16.7 4.00 lbs. Honey 1.042 0
8.3 2.00 lbs. Aromatic Malt Belgium 1.036 19
8.3 2.00 lbs. Munich Malt Germany 1.037 8
Potential represented as SG per pound per gallon.
Hops
Amount Name Form Alpha IBU Boil Time
--------------------------------------------------------------------------
1.00 oz. Horizon Pellet 13.00 48.2 60 min.
0.50 oz. Hallertauer Mittelfruh Whole 4.50 2.0 15 min.
Extras
Amount Name Type Time
--------------------------------------------------------------------------
0.50 Oz Bitter Orange Peel Spice 10 Min.(boil)
0.75 Oz Corriander Seed Spice 10 Min.(boil)
0.50 Oz Bitter Orange Peel Spice 2 Min.(boil)
0.75 Oz Corriander Seed Spice 2 Min.(boil)
Yeast
-----
WYeast 3864
Mash Schedule
-------------
Mash Type: Single Step
Grain Lbs: 20.00
Water Qts: 23.00 - Before Additional Infusions
Water Gal: 5.75 - Before Additional Infusions
Qts Water Per Lbs Grain: 1.15 - Before Additional Infusions
Saccharification Rest Temp : 150 Time: 90
Mash-out Rest Temp : 168 Time: 20
Sparge Temp : 170 Time: 0
Total Mash Volume Gal: 7.35 - Dough-In Infusion Only
