Establishing correct trigger length

I am deciding between long and medium 1911 triggers.  I use Zins grip . I use first joint to press my trigger, not pad.  Have avarage size hands and fingers .  How do You correctly establish trigger length that works for You ? Also , when ED Brown style beavertail is installed on s STD 1911 , does it increase or decrease trigger reach compared to std grip safety?

You can use any trigger length you like! I use short, med, long, and a shoe on med triggers. You learn how to squeeze them all differently. If you have short fingers then you have less choices. All grip safeties vary from manufacturers. It's a crap shoot on which one will reduce length or add length.
Jon

I find that I settle on an extremely consistent 2.8 inches, measured from the shortest point at the back of the grip (where the web of my thumb-to-forefinger rests, to the center of the trigger curve. To measure, I use a caliper and move it around until I get the shortest span. It's rather uncanny, no matter what pistol I like, it always ends up within a few hundredths of an inch to there. That number is just about the length of my right index finger, interestingly.

If you've never handled this new pistol, you may have to guess a bit.

I have used short, mediums and longs over the years. Each guns seems to be a little different. However, I select the trigger length for the specific gun on trying each in dry fire and seeing which length gives me the least dot movement. Generally, I end up with a long and my hand and fingers are longer and not wide.

It all depends on the length and width of your grip, the size of your hand and fingers.  The only absolute is to press straight back every time.

I also noticed that with STD grip safety ( like my Les Baer Hardball model )  Medium trigger feels better than long trigger.  But my pistols with beavertail safety are fine with medium or long .  I guess it is gun, grip specific