One thing addicts to CNS depressants need to be careful of is taking a high dose of any stimulant. Now this is not necessarily going to kill you, but what can result can be extremely uncomfortable. Many opiate users report "I hate the racing thoughts" "I had a panic attack." "Thought I was going to die" etc.
So what will happen is they will take a bigger dose of their depressant and the result is sometimes fatal or otherwise not good. Classic speed ball users died from either respiratory depression off the Heroin or cardiac arrest/myocardial infarction from cocaine. Even if a fatter hit of the depressant is not fatal, why would you want to raise your tolerance any higher?
Now as far as the pleasure of your roll, you are at the knife's end of probably needing a normal dose of your DOC before taking ecstasy in order to have a pleasurable experience. Depressant addiction really takes away from fun stimulants and certain psychedelics alike. It's much like dampening fire wood.
You'll really need to take a rain check on this one or make sure you watch the dose on either drug and be satisfied with less intensity. It's very easy to OD when you hardly feel side effects.