Take a look a this ST7032i I2C Display implementation http://www.esp8266-projects.com/2015/03/display-time-st7032i-i2c-lcd-display.html the LCD_Write and LCD_Print_Values functions might help you with printing numbers.
Available on Tindie: https://www.tindie.com/products/nEXT_EVO1/universal-ac-mains-dimmer-mpdmv41/