Any expert can tell me about the ExtJS5.1 and SA3.2 multi build solution ? :)

Hi guys, we use SA3.0 and SA3.1 to develop over 20 Touch projects, we always use "Ext.app.Profile" to build different UI for Tablet and Phone device. Now we upgrade to SA3.2 and know that ExtJS5.1( sencha CMD 5 ) also can build for different target( Desktop, Phone, Tablet ), then we try.

But the point is: Seems use ExtJS 5.1 ( Ext.app.Profile ) to build the project, the app.js size is supper big !!! ( only use 3 Ext Containers for each profile, just a the demo, nothing else, the production version app.js already 1.1MB ), in the past our very complex Touch project app.js size NEVER over 800KB.

The purpose we want to use SA3.2 ExtJS5.1 Project is that: we build a new project for client which the app will cross over Desktop/Phone/Tablet, and we "try" do that in ONE project and build for different target, is sound very convenient , but now the "whole solution app.js" size not acceptable....

And I read the SenchaCMD5 new feature, there is a "builds" option in app.json file, but ...the API document only show the case for building different themes...can it build for different target ? ( mean "Desktop version app.js", "Phone version app.js" and "Tablet version app.js", each of them ONLY compile the views/models/controllers belongs to specified profile !!! )

Is any one can give us a better solution or suggestion on this purpose ? We're look forward to listen it

Any expert can tell me about the ExtJS5.1 and SA3.2 multi build solution ? :)