When compiling a CUDA program in Eclipse and faced with the option to choose between SASS and PTX, how should I select?

I am using Orin NX devkit and 20.04 Linux.
When compiling with Eclipse, which version of SASS and PTX should I choose?

Orin Nx is SM 8.7.

Will there be any issues if I choose a lower version?

It depends “how much lower”. PTX of a lower version will be JIT compiled by the driver in order to run on newer hardware, but some newer features may go unused.

See here.