Put 2.5 gals in a keg and 21, 12oz bottles for a total of about 4.5 gals packaged.
Based on boiling 5.90 gallonsliters at 1.076 for 60 minutes, this will decrease your wort by 0.00 gallonsliters, bringing your after boil OG to 1.076. You wanted an OG of 1.087. It looks like it will be under.