I just can’t find how to resize the GUI in logic! I am working on a 49 inch screen and the font is very small so really would like to resize the plugin as I am using it very much for sound design!
Yeah, so it can be confusing with Logic Pro since Logic opens all plugins in a “container” window, therefore creating an extra border. Next to this, the VELA interface itself does not really indicates the resizing area ( although your mouse cursor will change to a double axes arrow to indicate the resizable corner )
Don’t place your mouse over the Logic plugin window right-bottom corner ( RED ) → 
But instead, place your mouse over the VELA window right-bottom corner ( GREEN ) → 
Hope this helps !
Cheers 