Help with hop additions for Old Jubilation clone

[sharkmuncher]

So seeing as Avery is not longer distributed in NE, I decided to try my hand at making an Old Jubilation clone of the coming holiday season.
So, from Avery Website:

Beer Style: English Old Ale
Hop Variety: Bullion
Malt Variety: Two-row barley, special roast, black, chocolate, victory
OG: 1.074 ABV: 8.3% IBUs: 30
Color: Mahogany

and and email to Avery

Old Jubilation

OG: 1.074
AE: 1.014

Grist:
Pale 2-Row – 88.3%
Black Malt – 0.7%
Special Roast – 4.7%
Victory – 4.7%
Chocolate Malt – 1.6%

Hops:
60min – Bullion (7.6% AA) – 0.34 oz
30min – Bullion (7.6% AA) – 0.52 oz
0min – Bullion (7.6% AA) – 1.01 oz

Yeast – California
Ferm Temp – 70F

I was able to get the grains all set up in beersmith, but I having difficulty with the hops. Bullion are apparently near impossible to find, so I was thinking of substituting with either Northern Brewer or Columbus.
So I have a few questions here:
1. Which of these would be the better substitution (it may not matter much in such a low hop beer)
2. What is the best way to go about calculating for differences in IBU? The 60 min addition should be a pretty much straight conversion since it doesn't contribute much for flavor, but what about the 30 and 0? Seeing as something like Columbus is ~12% AA, I would add about 60% less hops, but at this point it would start to effect flavor as well. Along these same lines, would I even change the amount of hops @ the 0 min addition seeing as there is so little IBU and almost all flavor and aroma contribution?
3. Finally, when I plug those #s for the bullion hops into beersmith, I only get about 14-21 IBU depending on the formula. is this something that needs to be adjusted for when converting from a large batch to 5 gallons ie if they just did a straight conversion of their full batch to 5 gallons, will it throw the IBUs off? Or should I just trust the brewer and go by the recipe?

[Hoser]

Found them!
http://www.rebelbrewer.com/shoppingcart ... llets.html

Otherwise Northern Brewer would be an acceptable substitute, IMHO

As for the difference in IBUs, are they giving you calculated or measured? I imagine there is some isomerization at the 0 minute addition because the probably do a 20 minute whirlpool and this may be causing the difference if they are giving you the measured IBUs?. Check the Majaraja CYBI to see if Adam Avery mentions doing a Whirlpool. Push all of the hop additions back 20 minutes and see what Beersmith gives you for numbers then. 60 to 80, 30 to 50, and 0 to a 20 minute addition.

[sharkmuncher]

Found them!
http://www.rebelbrewer.com/shoppingcart ... llets.html

Otherwise Northern Brewer would be an acceptable substitute, IMHO

As for the difference in IBUs, are they giving you calculated or measured? I imagine there is some isomerization at the 0 minute addition because the probably do a 20 minute whirlpool and this may be causing the difference if they are giving you the measured IBUs?. Check the Majaraja CYBI to see if Adam Avery mentions doing a Whirlpool. Push all of the hop additions back 20 minutes and see what Beersmith gives you for numbers then. 60 to 80, 30 to 50, and 0 to a 20 minute addition.

Wow, not only did you find the hops that I looked all over for, the adding 20min for the whirlpool (which I'm pretty sure was indeed mentioned on the CYBI episode) brings the IBUs right up to 32. I never would have though about that. So when I brew this, should I still throw in that last addition at FO if I use a wort chiller, or should I give them 10 min or so in the boil first?

[Hoser]

Yup, it gets you over 30. Just thru the numbers into Promash quick ( I am an archaic brewer with my software ). It gave me 38.5 IBUs using the Rager formula with pellet hops, which is probably about right depending on the formula that the brewers use and gave you. Rager is typically higher than Tinseth. It also depends on if they are using whole hops as this comes out to be 33 due to a lower utilization. It seems like quite commonly on CYBI JZ and Tasty generally overshoot the IBUs the brewers give them by 5. So going by that logic it works.

[brewinhard]

Also another good idea is to add your hop additions into your software backwards from 0 min through flavor additons then into the 60 min. boiling. For example if you are changing the AA% of the required hops (either you have to substitute for variety or percentage difference) then you would add the same amount of hops called for in the recipe at each time beginning with 0 min all the way up to say 30 min additions or so. Then simply adjust the 60 min addition to help you reach the targeted IBU level in the finished beer recipe.