We ran into a similar setup and ended up using the same code base for dev/test/prod but using the PSUHeader region for the .universal files.
for example in the variables.ps1 I have the following.
#region PSUHeader
switch ($ENV:COMPUTERNAME) {
"PSU1" {
$Environment = "Prod"
$CurrentHostName = "https://hostname.com"
}
"PSU2" {
$Environment = "Test"
$CurrentHostName = "https://hostname.com
}
Default {
$Environment = "Dev"
$CurrentHostName = "http://localhost:5000"
}
}
New-PSUVariable -Name "HostName" -Value $CurrentHostName -Description "Hostname of the PSU instance"
New-PSUVariable -Name "Environment" -Value $Environment -Description "PSU environment type"
#endregion