Interesting case 
one of the first things you want to consider is how âsynchronousâ you want that to happen.
one way would be to play something through as many âtone generatingâ devices you have and record them om separate tracks synchronously.
OR
record one part, hearing it through an amp as reference but also recording the dry signal from your guitar. you can record several takes of one track, replay in your daw with some basic amp sim just to hear whatâs going on and edit/cut/etc the guitar pieces and comp them to tracks you like (this price from the first take, that piece form the second take etc). you probably end up having 2 max 3 good takes by cutting and pasting the pieces together.
when you achieved your âbrilliance on the basicsâ, a few but solid guitar tracks, you turn off the amp sim and you have dry signals again you can send trough each physical amp and play with the settings. If all settings are good you can now âre-ampâ â run the dry signal through an amp and record id. listen to it, tweak some drive or EQ when needed etc.
When you want to do it LIVE, youâre doing this all at once of course.
Using 2 amps live can offer real fun blending options.
your new pre-amp offers a lot of scenarioâs and your amps can be flexible too, disconnecting their speakers (which is, in combo amps often not hard wired but a piece of speaker cable going from power amp section which you can detach like regular jacks. itâs a bit shot though).
To use the Creamback, you better put it in a cabinet. to use it properly you either
- need to connect the cabinet with the correct power amp output on the Synergy amp (we can lookup the correct impedance)
- get your hands on a separate power amp so you can âmake your pre-amp louderâ( or attach quasi any drive pedal in front of it.) and then attach the cabinet to this power amp.
Even so, in theory, when you connect the pre-amp to the âreturnâ of the fx loop of the Synergy (or the Katana if it has one), you can use the Synergy as power amp.
perhaps, at some point, a simple passive splitter (like those from Lehle) comes in handy to split your dry guitar signal into 2 quality signals without the need to power that little block. you can run that into your scarlet to record your dry while jamming and have the other go to an amp or you can go to 2 separate amps and go for stereo character blends etc
you might need to buy some speaker cable of decent length when you want to use a separate cabinet or you want to use the speaker inside a combo amp. They handle more power than your regular guitar cable but the jacks look the same so be wary. speaker cable tends to feel a bit less flexible
So Bottom line is
- decide on your workflow
- map for each of your devices which roles and components it has
- see the many options you have in front of you, using pre-amp here, power and there, speakers hereâŚ
**
IMPORTANT NOTES to AVOID DAMAGE
- always use speaker cable to go from power amp to speaker
- dont use a power amp with a correct speaker attached to it. (speaker or a load that emulates a speaker)
- donât connect a power amp to a powered input of a PA speaker
- check the correct impedance; thatâs why power amp outputs often have 4/8/16 ohm outputs to choose from)
**
this wonât cause damage, except maybe to your ears or brain 
- turn of IR (cabinet ism) when you plan to run your signal through real speakers
- turn on IR if you plan not to pass through real speakers
In al your scenarioâs, you can always use the balanced out to connect your amp with an audio interface or mixing desk. this signal will be safe (not high powered) so that can go into your other devices. check the docu of your gear to check whether it has some built in speaker simulation. in the case of your pre-amp, it will probably use the IR by default ofr maybe you have the option to turn that on and off as well.
(this is starting to sound like a Live Club subject? :D)
