Is anyone aware of proper tools that lets edit/patch 64bit binaries using assembly instruction.

For example, for 32 bit binaries we could press "space-bar" in Olly and type "mov ebx, eax". Since, Olly will not handle 64bit binaries, what are the other sane options to debug and patch the 64bit cousins ?

My problem is:
- I know the location to patch.
- I know the x68 ASM code to patch with.
- I *DONT* know the corresponding 64bit translation of the ASM.

Options I have tried:
- Visual DuxCore Debugger (doesn't seem to let edit/patch)
- Manually editing byte in 64 bit IDA disassembly and checking the 64 bit translation. (with limited success)