New to Skymiles - Maximizing JFK-BKK

I am new to skymiles, we (2) are flying to BKK from JFK in August or September (dates are not set). We have about 130k in miles to use.

We are looking to buy tickets and then use gifted miles to upgrade. The goal is to have a segment or two where we have Delta's Flatbed seats.

Any tips or specific flight/fare class suggestions? Tickets are currently about $1300.

I grew up flying Delta but have not been on one of their flights in about a decade.