Я обычно делаю это следующим образом:
Pos_size=[100 100 900 400]; %this is just a variable I put at the top of the file so I don't have to look through my script to change it.
%[X1 Y1 width heigth] X1 is right side position, Y1 is bottom side position on your screen,
%X1 and Y1 you use to center the figure when it opens.
h1=figure(1); %before your subplot, opens a figure and saves the handle as h1, alternatively you can use hf=gcf; as it will grab the handle of the latest figure
set(h1,'Position',Pos_size); %sets the position and size of the figure with handle h1
Если вы поместите это выше своих подзаголовков, это должно работать