Tank Engine

I have the SL6 and ride a 56, I am 1.84m tall and suits me well. My mate also has one and he is 1.78m tall and rides a 54. I reckon a 56 would be perfect but dont hold me to it

https://www.cyclelab.com/product/giro-empire-slx-white-black-road-shoe (R1300) https://www.cwcycles.co.za/product/continental-gp5000-tubeless-tyre (R550) https://www.cwcycles.co.za/product/stages-power-meter-left-ultegra-r8000-v3 (R4000) Thanks