Some good info here: Learning Nurbs Topology for Paneling Projects - #10 by Michael_Pryor
Considering a grid is by definition 4 sides. You really need to first think about how you imagine this grid to resolve and end on your shape (maybe by sketch). Only from that point can we help further in any meaningful way. There are too many possible solutions otherwise.
Pretty succinct in my wording. Problem is very straightforward
The problem, yes. The solution, no. Really depends on aesthetics at this point, show us what you think it might look like. We are here to help.