I have one of those PX4’s they are great little machines, dont know how to get the sound you want, i just use the presets, for practice use you cant beat it, the sounds through headphones are incredible, ive noticed that the price of them are begining to come down, which usualy means a new PX5 is on the way..

Jon, just in case you don’t get a reply here that sorts it for you, have a look also at the plexi palace forum. They have a category “fx and the signal chain” and a sub-cat “Signature tone”. You might get some help there, although a lot of the people I know on PP are not fond of multi-FX.