All grain partial boil?

I've upgraded to a 30 gallon conical fermenter.  My existing front end has a 15 gallon capacity.  How do I configure my equipment profile (or scale my sessions correctly) in BS2 so I can carry out a regular boil and account for top off water in the fermentor for say 20 - 25 gallons of finished product?  I guess it would be an all grain partial boil so to speak?

I'd like to get full use out of the conical if I can.

Thanks!

You're essentially just brewing a higher gravity beer and then watering it down in the fermenter. You would just enter your 15 gallon recipe as you normally would and then, in your equipment profile, enter your water addition as top up water in the Fermenter/bottling volumes section.

You'll need to make some corrections for your hop additions, due to the the dilution factor. Your hop utilization will also suffer because of the higher gravity boil, but BS will calculate that. Another consideration may be lower mash efficiency due to the higher gravity, much like you'd expect in a RIS or Barleywine.

Personally, I'd be tempted to just do a double batch if I were intent on filling the conical, but that's me. Starting the second mash as soon as the first is done and the same with the boil  would basically add the mash, boil and chill time with the in betweens. Likely a couple of hours total.

You're right on the double batch...  I was originally going to run that route, but figured there was a way in BS to do the calculations and see what the effects would be. 

On a full fermenter run, a double batch would definitely be a better solution.  On something just a little over what I would normally make, say 15 gallons - the top off calculations will come in handy.

Thanks for the help, I'll play with this and see where the rabbit trail leads!