Long 75mm runs/short 125mm vs shorter 75mm/125mm with elbows

[Jambutty]

Bit of a silly question. Probably no best way but here goes. 
 

I have a BROOKVENT airstream Ace MEV with 1 x 125mm external connection and 11 75mm inlets. 
I can position the fan so the 125mm can extract directly outside with no bends and a 1.5m duct run but all 75mm ducts will have to be approx 2m longer

 

Or I can position it and use 2 125mm 90 elbows with approx 3.5m of external duct length but all 75mm ducts will be 2m shorter

 

Will it actually matter or am I over thinking it

[JohnMo]

You really need to do the math. Look up the allowable pressure drops for your system, then look at the pressure drops across the different duct sections and any bends. Otherwise it's all guess work, rubbish in rubbish out.