You can customize your instance by modifying the constants under the constant block in index.js. The code looks like this:

// ------------------- CONSTANT BLOCK EDIT IF RUNNING ON A CUSTOM SYSTEM ------------------
// Grading data
var MAX_KNOWLEDGE_LEVEL = 4;
var MAX_POINTS_ON_CHARACTER = 0.25;
var ADD_POINTS_ON_ERROR_3_4 = 0.1875; // 3/4 of 0.25
var ADD_POINTS_ON_ERROR_1_2 = 0.125; // 1/2 or 2/4 of 0.25
var ADD_POINTS_ON_ERROR_1_3 = 0.0625; // 1/3 of 0.25

// Specific writer data
var CARD_WRITER_STROKE_ANIMATION_SPEED = 1.25;
var CARD_WRITER_DELAY_BETWEEN_STROKES = 50;
var CARD_DEFAULT_CHARACTER = "是"
var CARD_DEFAULT_PREVIEW_NAME = "Preview Name"

// Universal writer data
var CARD_WRITER_SIZE = 100;
var WRITER_PADDING = 5;
var WRITER_RADICAL_COLOUR = "#c87e74";
var WRITER_SLEEP_AFTER_COMPLETE = 1200; // In ms

// Error data
var WRITER_SHOW_HINT_ON_ERRORS = 3;
var WRITER_SHOW_HINT_ON_ERRORS_LVL_3 = 1;

// Padding to be subtracted when calculating the main page layout
var MAIN_PAGE_TOP_PADDING = 10;

// ---------------------------------- CONSTANT BLOCK END ----------------------------------

do keep in mind that messing with the grading settings may lead to some logical breakages in the application. Setting the grading level above 4 in particular will simply increase the upper points limit but not change functionality in any way. Lowering it will disable advanced levels.