Adjacent Sums

1. Place the numbers 1 thru 9 in a 3x3 grid such that every adjacent pair (excluding diagonals) has a different sum.
2. Your first solution will not use three possible sums. Repeat #1, using these sums.
3. What is the largest possible difference between two adjacent numbers in the grid? Can you find solutions with this difference to satisfy #1 and #2 above?