Is it possible to edit your height on a dynasty mode?

I'm wondering if there's a way to change your height in a dynasty mode, maybe editting the .DBF files? Or something? I can change sigshots, hotspots, something like that using DB Commander, but i can't seem to find where to edit the height. Is it even possible?

It's possible. To edit the height, you have to open appearance.dbf file. But before that, find the player you want to change height in players.dbf and note his player ID. Then in the appearance.dbf file, find this ID and in the column "HEIGHT" you have player's height in inches.

what's the max value of height that can be input?

I believe 7'6" or possibly 7'7" is the maximum "stable" height you can use. I believe some people have encountered issues when creating players 8' and over.