Hello Mannie,
changing the size of the graph by program is possible.
To do so, create an property node at the front panel: right click -> create property node -> plot area -> size -> all elements
Drag down the list in the block diagram an you'll get the variables height and width. Change them to write by right clicking.
The size of the window can determined by using a property node too: (block diagram) programming -> application control -> property node
Right click -> link to pane. After that right click -> properties -> bounds -> height / width.
Good luck.
Regards
Ralf