Get better stadimeter readings in low res?
 

i am currently playing with my notebook and it has a resolution of 1366 x 768.. i was trying to do some patrolling without map contact update and i noticed that most of the times, when finding distance, i go off hundreds of meters from the real measure simply because the ship is not well defined on my screen (= no easy mast height finding)
what should i do to fix this problem? i can't find a mod that increases the periscope zoom level beyond 6x and without that is really hard for me to take accurate readings.. (like 300+ meters off in a 3-4km away ship)