Questions about Productive Enterprises and Trade in Floris Mod

So I have three questions.

1. Is there any reason to NOT build dyeworks in all the cities? It seems to me that over a long enough period of time, the investment will be paid off, so should I just go for the investment that will make the most money, period?

2. Sort of an addition to the previous question; should I diversify my productive enterprises? Build an ironworks one place, a brewery somewhere else, so on and so. It seems like diversifying investments MIGHT be a good idea? I really don't understand how the economy in Warband/Floris works, so not sure if this matters.

3. How much can trade goods prices fluctuate from the norm? I've been trying to use this trade route guide. However ALL of the trade goods seem to cost more than they supposedly should (no, not just high quality goods, ALL of the goods). When I try to follow the guide, nothing is as cheap or sells as well as the guide suggests.

Thanks for any info! :)