PC monitors of all kinds.

I bought a new 144 HZ gaming monitor (Dell S2719DGF) to play First person shooters and now i dont know if i should turn vsync on or off when freesync is activated, and if i should use FRTC, which is AMDs frame limiter, or an ingame frame limiter.
I have FRTC on and set at 141 FPS in the radeon settings atm, but i dont know if that make sense tho.

I got also a new Radeon Vega 56, but the rest of the hardware is a bit older:
Cpu INTEL Core i5 4570 PC1150 6MB Cache 3,2GHz
ASRock H87 Pro4 1150 ATX
Ram DIMM DDR3 Crucial 16GB / 1600Mhz Ballistix Sport

I play in full hd resolution.

Anyone knows what the best settings are for me?