Hi Tom,
I just did a test. Boomi retries the message twice from q1, then moves it to DMQ #q1 and then removes the message after 60 seconds from #q1. I assume this is the way it should work right? This is how we implemented this on ActiveMQ in the past.
Queue name = q1
Respect TTL=false
TTL=0
Retries=2
DMQ name =#q1
Queue name = #q1
Respect TTL=true
TTL=60 seconds
Retries=0
DMQ name =#DEAD_MSG_QUEUE