Low preboil gravitiy/ help

This last weekend I missed my preboil gravity by quite a bit. The main reason is I changed a value in Beer Smith for some reason and didn't change it back before brew day I always do a gravity check of my final runnings, and it was 1030 so I know I have plenty of sugar left in the mash. I also have 9lb of DME sitting here that I could have used. So the question is..

1. If I want to do just run of more wort and boil longer, how can I figure out how much more to run off?

2. If I use DME how do i figure out how much to add?

I have Beer Smith if that helps. Thanks for any help/advice on this.

DME on average adds about 42 gravity points per pound per gallon. So for every pound you add (in a 5 gallon batch) you're adding add 8.4 gravity points to the Specific Gravity. So if you needed to raise your preboil gravity to say, 1.050 you would need to add 2.4 pounds of DME. 20gravity points/8.4gravity points per pound=2.4 pounds

DME on average adds about 42 gravity points per pound per gallon. So for every pound you add (in a 5 gallon batch) you're adding add 8.4 gravity points to the Specific Gravity. So if you needed to raise your preboil gravity to say, 1.050 you would need to add 2.4 pounds of DME. 20gravity points/8.4gravity points per pound=2.4 pounds

pete and repete were on a boat. pete fell off, who was left?

Repete was left.

Where Repeat was I couldn't tell you.

I've read you can keep sparging as long as your gravity is 1.010 or higher. Too much lower and you get tannin extraction.