dual use PID controller??

I want to build a PID controller that I can upgrade later but get set up now with room for expansion. I have the 2352 from Auberins with 25A SSR and heat sink.
I would like to set it up much like Jkarps Brutus 20 so I can experiment with smaller 3 gallon batches because sometimes I just don't want 5gallons of some beer and with the PID controlling a plug I will use it for Sous Vide as well. I plan on using a 2kW 120v element so I can use it on my normal 20A circuit in the kitchen.
I want to expand it later possibly to use 240V so I could run a 4500 or 5000W in my 15g kettle but use the same PID for both to keep cost down so the wife doesn't kill me.
Questions:
Should I run 2 SSR off the PID with a switch on each to chose which SSR is on or run a DPDT switch after the PID to control which outlet it sends power to(240 or 120v). If I run the DPDT switch I'll return my 25A for a 40A SSR and heatsink.
I thought I could run the hot from 120v and one lead from 240 to the same contact terminal with the other hot lead from 240 to the other terminal of 240v so I could have a on/off switch to kill it with. I would obviously only use one at a time120 or 240.
I plan to use a simple outlet with a switch for the pump and yes only one 240v element.
Sorry I hope my questions are clear, anyone know of a similar wiring diagram that would work.

your questions are very confusing and i really dont know what you are trying to do, but here is some info that may help...

if you are running a 240v element on 120v, devide the rated wattage@240v by 4 to get the wattage at 120v. so a 4000w 240v element will be a 1000w element if plugged into 120v.

a 240v line is really two 120v lines that are 180 degrees out of phase with each other. so you can think about it as having -120v, neutral, and +120v. the voltage potential between neutral and either of the 120v lines is obviously 120v. the voltage potential between -120 and +120 is, you guessed it, 240v.

so if you wanted to swtich between 120 and 240 on a single element, you would wire one side to a hot 120v line, and the other side would go to a switch, which would connect the other terminal to either neutral (for 120v operation), or to the other 120v line (for full 240v operation). you should also have some additional safty devices like contactors and such, but that is basically how to make it work.

to control two SSRs with one PID controller, you would want one SPDT switch so that you could select either one SSR, or the other, but not both. if you have two switches, one for each SSR, it would be possible to turn both SSRs on at once. with one switch, its impossible to make that mistake. its up to you which way you prefer.

Sorry, my question was a confusing jumbled mess.
Basically I want to be able to hook this up indoors on a 120v outlet to my 6gallon kettle with a 2000w element one day to make a small 3 gallon batch of beer then have the ability to go out the next day in the garage and hook it up to my 240v outlet to power a 4500w element in my 15 gallon kettle.
I like your idea of the SPDT switch much better so I can't power both SSR's at the same time.