I’ve tried my best to read as much as I can, however everyone uses their gear so differently so it’s been difficult.
I’m trying to use my laptop running reaper with the FX to play a track and then record the output from the FX into another track.
I can’t seem to get it work either with overbridge or via USB audio. I’m also unsure if USB will return the output. I would really appreciate some help and guidance with setting up the routing in reaper if it’s possible.
Thanks in advance.
I never used overbridge with AH+FX but what you want can work with usb class compliant.
You need to set your AH+FX as interface for both inputs and outputs into option => preferences => audio => devices
Then the track you need to process has to be send to the master of reaper which will be output into AH+FX usb input.
To record this, create a track, set the input to stereo => 1/2 !!!beware of feedback so the best is to bypass the send to the master of reaper of this track while recording!!! and then, it’s the normal procedure of recording on reaper. You need to arm the track rec then rec.
The con of this method is you need to listen to your processed sound directly on the Syntakt output. It’s not an optimal way but it can work. I’ll try overbridge with AH+FX to see if the process could be simplified and more elegant.
And i tried the overbridge way, way more easy and elegant ! 
So you need to have the last version of overbridge to support last firmware of AH+FX.
On reaper, create an audio track you want to process. On the FX part, set the AH+FX VST like a standard VST, if everything is standing correctly, now AH+FX act as a vst and process the sound of the track. To record it, the simplest solution is to create a second track. Send the first one to the second by a drag and drop from the “route” icon of track 1 to track 2. Now the audio from track 1 is send directly to track 2 (and also master 
). To record the audio on track 2, you need to arm it and send the record input to “ouput 1/2” (this is the most bizarre part of reaper imo, an audio routing not intuitive and logical at all) and then you can record your audio processed by AH+FX. Hope it can help.
Got it working. Thanks so much for your help. I really appreciate it 