I was referring to the output and not the input. I was thinking that if you were using a media player such as WinAmp, or VLC then perhaps the network buffer size could be changed. Scratch that question because I see now that Broadcastify uses a HTML5 player and Advance Player. They used to let the user select an external player.
How much delay are you seeing? If using the HTML5 player, try using the Advanced Player. You should see the latency decrease. My experience with the Advance Player is that the latency is about a second or less.
No setting in ProScan to adjust the audio / text tag sync.
{edit} I have experence with the Advance Player because my ProScan Web Server webpage uses it too.