What Springs to run with 5100's

I have a 98 4x4. I just replaced the rear shocks with the 5100's and gettting ready to install a Skyjacker TRC25S 2.5" leaf pack. I have the adjustable 5100's for the front and I know my spring's are shot. I have been looking at the Old man emu springs b/c they are in my budget. I plan on getting a brush guard or bull bar eventually on the front end. Should I get the the 880 881 or 882's? Also once you suggest one please let me know what to set the billy at when I install everything to achieve a level look.
Thanks in advance!!

 

Can I ask why? and what would I want to set the billy at?

 

So if I run the 881's where should the billys be set at?

 

i run 881's on my 04 double cab...gave me 2 inches in the front...bilstein 5100's set at stock height(bottom clip)........and i have a brush guard(cheap kind)....now if you are getting a plate bumper..that'll make a difference....get the 882's for the weight of the bumper.