AutoCAD Visual LISP / AutoLISP :: Create Custom Message Box With Variable Width And Height

I am trying to create a custom message box with variable width and height by passing width height title and list of text. I can get the routine to work if I use preset width and height, but would like to make the box adjustable.

Here is what I have so far -

;--dialog box--

MYmessage :dialog{
label="Custom message box";
:column {
:text {
key="MY_message_Title";
fixed_width_font=true;
[code].......