gauge railway workshop to yard

Hello all

Yup really niche question this.

Friend re-concreting his workshop floor, and intends to lay
mine-railway tracks in it.  Which runs out into the yard and enables
machines which make a mess to be wheeled-out from stored safe and dry
in the workshop to working some distance away given associated dust
when running.

Two gauges seem to be in use here - 18inch and 2ft (24inch)
(* 18 25.4) ;; 457.2 ;; 457 mm gauge
(* 24 25.4) ;; 609.5999999999999 ;; 610 mm gauge

Wheels & wagons etc available both gauges.
Though 18inch maybe more common in the very compact tin mines (the
lodes are narrow).

Anyone know of an argument to choose one gauge over another?

I'd have thought maybe the smaller gauge as seems big enough for
smallish hammer-mill, etc.; takes less space; and can have tighter
corners outside the workshop.

What experience does anyone have suggesting best choice?

Regards,
Rich S