Preferably you should have 3000psi available, 2000 will do it at a push but you may struggle on some difficult jobs. Heat is a benefit although not essential.
You need to use very good safe chemicals which aren't cheap, around 30 quid for 5 litres.
There are a few pitfalls to watch out for the most important is to prevent damage to the underlying surface and also ghosting which is when you have managed to get rid of the paint but have left an etched area which contrasts with the surrounding area.
We don't do much ourselves I would suggest contacting some of the chemical manufacturers who will provide you with info and also get onto some of the websites of companies already doing it where you can glean quite a bit info.