System variables have a fixed defaults and must be set each time you open a file or click on new;
Some system variables are stored with the file. If this is the case you must change the variable and resave it.
autoexec lisp functions are in this file
This file replaces file with same name in this directory
2 variables are already set around line 18 and line 46
you can use a text editor like notepad to edit this file.
you can look for lines (setvar "LUPREC" 4)
Then you can add a lisp programming line like this after each of the two lines you find in the file.
(setvar "FILLETRAD" 0.5)
Note this file is replaced every time you run the setup so save a copy somewhere else too incase you need to reset your settings or need to reinstall the program for some reason