Belgian Brown Advice

Hey friends. I have this unique situation where I am leaving town for three months and plan to get a mildly sour beer going for extended fermentation. After looking at many recipes (including the Nostradamus in the Brew like a Monk book) and inspiration from recipes here, I came up with this. I am hoping to brew tomorrow, ferment on 1056 for 10-12 days then rack to secondary on the Roselare mix. I leave a day or two after that (X-mas eve) and won't be back in town for 3 or more months. My hope was to rack it at or above 1.020 so the Brett/Lacto/Pedio have something to play with. If it is too low I will add more sugar (was thinking another 1/2# Turbinado boiled in water or some sherry wine, since one of the yeasts is a sherry strain).

I would greatly appreciate any advice you have. This is my first wild brew attempt and also extended fermentation. After getting back in April I might rack again with some soaked oak chips.

BeerSmith 2 Recipe Printout - BeerSmith Home Brewing Software, Recipes, Podcast and Blog
Recipe: Bilbo Belgian Brown Ale
Brewer: Jim Thompson
Asst Brewer:
Style: Flanders Brown Ale/Oud Bruin
TYPE: All Grain
Taste: (30.0)

Recipe Specifications
--------------------------
Boil Size: 8.76 gal
Post Boil Volume: 6.76 gal
Batch Size (fermenter): 5.50 gal
Bottling Volume: 5.00 gal
Estimated OG: 1.060 SG
Estimated Color: 18.3 SRM
Estimated IBU: 21.3 IBUs
Brewhouse Efficiency: 72.00 %
Est Mash Efficiency: 87.1 %
Boil Time: 60 Minutes

Ingredients:
------------
Amt Name Type # %/IBU
5 lbs Munich Malt - 20L (20.0 SRM) Grain 1 40.0 %
4 lbs Pilsner (2 Row) Bel (2.0 SRM) Grain 2 32.0 %
1 lbs Cara-Pils/Dextrine (2.0 SRM) Grain 3 8.0 %
8.0 oz Aromatic Malt (26.0 SRM) Grain 4 4.0 %
8.0 oz Caramunich Malt (56.0 SRM) Grain 5 4.0 %
8.0 oz Special B Malt (180.0 SRM) Grain 6 4.0 %
1 lbs Turbinado (10.0 SRM) Sugar 7 8.0 %
1.00 oz Goldings, B.C. [5.00 %] - Boil 60.0 min Hop 8 13.9 IBUs
1.00 Items Whirlfloc Tablet (Boil 20.0 mins) Fining 9 -
1.00 oz Saaz [4.00 %] - Boil 20.0 min Hop 10 7.4 IBUs
1.0 pkg American Ale (Wyeast Labs #1056) [124.21 Yeast 11 -
1.0 pkg Roselare Belgian Blend (Wyeast Labs #376 Yeast 12 -


Mash Schedule: Single Infusion, Full Body
Total Grain Weight: 12 lbs 8.0 oz
----------------------------
Name Description Step Temperature Step Time
Mash In Add 15.90 qt of water at 167.1 F 156.0 F 45 min
Mash Out Add 5.75 qt of water at 205.5 F 168.0 F 10 min

Sparge: Fly sparge with 5.11 gal water at 168.0 F
Notes:
------
Use WY1056 for 10 day primary, rack to secondary on Roselare for 3+ months

And yes my current BK setup loses up to 1G trub and deadspace. I am working on that (hence the high pre and post-boil volume).

Now I am confused. I just read this thread which suggests an extended primary ONLY on Roeselare yeast, no generic ale yeast, no racking. The idea of the yeast cake being extra food for the mixed bugs is intriguing.