Have you ever tried?
I use close up dioptres on viewfinder cameras very often, it’s easy.
+3 seems to be the most useful, that is 33cm from dioptre lens to subject with camera set to infinity.
I have a piece of string with a knot at 33cm and a loop in the other end to fix it to the cameras strap lug, hold the string out straight, move camera in till the right distance, drop the sting and press the button.
Obviously you need to set the subject off centre slightly to compensate for parallax but that is easy enough. Often I do this hand held and they are always in focus.
A folder with a few filters is a hell of a carry everywhere do everything (well most things) camera. 🙂