An example only to add weight to the 'know both' theme:
I moved from flying Lynx to (UK) Apache. The Lynx was a Westlands frame designed in metric with Rolls-Royce engines in imperial. The Apache, on the other hand is an entirely imperial airframe design with newer Rolls Royce engines in... you guessed it -metric!
I too was entirely educated in SI units. You just get used to it; the ability to do mental arithmentic is a pretty fundamental pilot skill anyway!
PP