what is a generaly acceptable file size for a php web page??
I don't think there has ever been some agreed upon standard regarding the size of web pages other than the smaller the better. However, not at the expense of saying or showing what you need.
As for functions, I think it's best to include them from different files. It's much easier to look at and focus on the logic of the program in genral when things are properly arranged.
Cheers,
BDKR