The size of the video window displayed on the consumer side is fixed with the expert assist SDK. If you wish to have better control of the V&V then you should use the Advanced SDK for V&V part in conjunction with the expert assist SDK for the co-browse.
I'm not sure what the assistOverlay you referenced is.
I downloaded the advance sdk and open the sample project, but I dont know where to change the video size is. And cant find it in here cisco-remote-expert-mobile-advance-developer-1151 either.
Can you give me an example? Is it okay to change the jar file by myself like what I already did, it's working fine.