Three Encoders

That should possible with a little bit knowledge for understanding C code. You will find links in this forum for different modifications.
e.g. https://github.com/sstaub/lighthack
https://github.com/Druuka/LightHack
You should also use a bigger LCD display with 2x40 chars.

Unfortunatley I have next to no understanding of C code but I will read through some of the scripts from those githubs and try and work out how to merge them together into something that fits my needs. Also I was thinking instead of an LCD display I could maybe just use a few LEDs that light up to indicate which page you are on and a single button to step through parameter pages rather than two, to save space and arduino pins.

Here is a modified version of Mr Staub's code that uses 4 encoders and a 4x20 screen, https://www.dropbox.com/s/5x7xkp378k13of6/lighthack_box2B__-_Bradv12.ino?dl=0 it runs nicely on a Teensy 3.5 board

Thank you very much, I have ordered some encoders and will give this a try

Is there a new place to find this file?  All I get from this link is "404 That file isn’t here anymore"

Sorry, I was moving stuff around on my harddrive and screwed up that link.  Try www.dropbox.com/.../AAAKp7YZ5xG3MbthP0BFwORea

This is a long shot here, but I'm using your code and I'm having some trouble. I wondered if you could help?

The third and fourth encoder are not working for me. All four of the buttons work for their appropriate parameter, but only the first two encoders are working with rotation. Any ideas?

the only thing I can think of is checking your soldering, sorry.

I'm sure the soldering is proper. It's giving me the error, "error, ProcessWheelCommand invalid parameter name: empty"

Where are you seeing the error? When compiling and uploading or in Eos?  Which version of Eos are you running?  I've only used mine on 2.9.1