Collage Customisation solved by Magic, but a question remains

After many years of frustration with printing from Elements, I have discovered a way to put a few photos on one shee, the way I want to. Comments welcome.

Customising a Collage in Photoshop Elements 2021

1 Launch Browser
2 Select three photos (use Ctrl+Click to add photos to selected ones)
3 Create (top right) -> Photo COllage
4 Choose a Landscape or Portrait layout on right and double-click to apply it
5 You are now at the Standard Collage setting and can move each photo within its frame

MAGIC Starts Here !!
6 Look bottom right and see layouts and Graphics are available.
7 Click on Advanced Mode (top left) and it changes to Basic Mode.
8 Now look bottom right and see that Layers is now also available. Click on Layers.
9 Select one of the layer header bars (eg _DZLandscape 1 or _DZPortrait 1).
10 Now you have control of a Frame in the collage, and can tilt it and size it. Magic !!!
11 Repeat on each frame you wish to alter. Don't forget to accept/reject change before selecting a diffent frame.

Question:-
The Collage is sized at 1800 x 1200 pixels.
How can this be changed, and can the default be increased to suit A4 paper ?