Imperial pumpkin porter

I made a porte Saturday evening and I want to add some vanilla bean. I also want to add some brown sugar. My question is should I hold off on the van bean for two weeks taste it and if it needs add more spices pumpkin and the van bean then? I'm going to wait till it slows a little to add 1lb of extra dark brown sugar. Here is the recipe I made up, it's a big one. And my plans at the bottom, let me know what you guys think.
12gal batch OG 1098
25lb 2row
6lb Vienna
4lb crystal 120
2lb chocolate malt
1lb black paten
10lb freshly baked pumpkin in mash
Amylase enzyme 3/4 tea in mash
1oz warrior at 60
1oz mosaic at 30
1 1/2oz ginger root at 10
1 1/2oz cinnamon at 5
3tea nutmeg at 5
3tea pumpkin pie spice at 5
Pitched 2 packs of whyeast that sat on stir plate for 12 hours
I want to add 1lb of extra dark brown sugar when fermentation slows along with 1 can of pumpkin. Check gravity and maybe pitch a white labs San Diego super yeast to finish it up.
Then add more spices to taste.

 

Well, any thoughts? Anyone?

 

I could be totally off but I believe your amounts of chocolate and black will clash with your desired pumpkin flavor. The vanilla bean calms those burnt toasty flavors nicely. But not sure what it will do with pumpkin and dark malts. I say go for it. You don't make good beer without experimenting. If it tastes horrible then you have a good ethanol base for "bio fuel".