I also have a Trutone that I bought after some research and recommendations. Always use your own caution, but I remember seeing some information purporting to be from Trutone engineering that the devices can output more than they are rated for and the published numbers in the specs are chosen to satisfy regulatory and certification matters. Not that I’d trust several hundred spacebucks worth of equipment to an internet anecdote, but I trust the manufacturing quality and reputation of the company that if you’re running at the advertised limits it will be OK. A long time ago in this forum someone also measured the operating current of the Duo and (without external devices) it was running well lower than the included power supply.
Don’t forget that the Duo uses center-positive power supply. (Many pedals, battery packs, etc use center-negative) The Trutone includes a polarity converter cable - make sure whatever you end up with can output the right polarity!