Is there an ideal window size for mobile?

Let's suppose you have a game similar to what is shown in the Flappy Birds demo. In the demo, the window size is 400 x 500. The game and the layout look appropriate when using Letterbox scaling, but Cocoon JS doesn't let you wrap with letterbox scaling. Scale outer mode looks OK in browser, but doesn't fit on a phone display. I tested on a Galaxy S5, and the scale outer mode appears to show a lot of space above and below the window size. However, if I adjust the window size to 1080 x 1920, then the game looks good on the S5.

The problem that I'm running into is that the memory usage greatly increases with the size of the window. A window size of 400 x 500 doesn't use much RAM. But increasing the size can make it unplayable on some devices.

I've read the tutorial for designing for a certain aspect ratio such as 4:3 or 16:9. I can use a 16:9 resolution as the window size, but any sizes lower than 1080 x 1920 will result in obstacles outside of the layout appearing on-screen.

Is there an ideal workaround to make up for the fact that CocoonJS doesn't support letterbox scaling? I used black letterbox images on the top, bottom, and right side.

Also, is there an ideal RAM usage amount? I know that you want to get it as low as possible. I built a game with 54.7 MB RAM usage and the game played great on devices with 2 GB RAM, but lagged on devices with 1 GB RAM.

Any suggestions for either question would be very helpful. Thanks in advance for taking the time to read and respond.

Either not use cocoonJS

Or try to place some elements dynamically with the viewport expressions so the game adapt itself to any kind of aspect ratio.

i have an advice for you , i have been u sing C2 for a long time and i have tried manything , the best solution is Outer scale , the best resolution for mobile platforms is 480x854 and with applying the Outer scale it will fit almost devices perfectly , if you don't want the white space in sides , use the anchor behavior for the objects that doesn't need to be at an exact position for example the HUD the background ... the Menu they can all have the anchore behavior , and for object you will position with event sheet use the viewport expressions , this will perfectly fit your game on almost devices.

This might be of use:

I use an addon window resizer for chrome, to quickly switch between different (browser)-resolutions to check what my app will look like across different devices..

You could try this

i have an advice for you , i have been u sing C2 for a long time and i have tried manything , the best solution is Outer scale , the best resolution for mobile platforms is 480x854 and with applying the Outer scale it will fit almost devices perfectly , if you don't want the white space in sides , use the anchor behavior for the objects that doesn't need to be at an exact position for example the HUD the background ... the Menu they can all have the anchore behavior , and for object you will position with event sheet use the viewport expressions , this will perfectly fit your game on almost devices.

Thanks for the tips — I found this video very helpful as well. It has worked beautifully for our game.

EDIT: I need more rep. Oh well. Go to You Tube and search for: "Construct 2, multiple screen sizes". You'll find a great tutorial as the first link.