Two of the same EPTX on an ATB boat is still completely unnecessary and thoroughly useless.
Aye; I'd toss in a ET1 instead of the second EPtS1 for a multipurpose heal that you can throw out when needed. Although I'm honestly not sure why you'd chose a vessel that isn't really like a cruiser to run an Aux2Bat build, more power to the OP if it works well. If you always run with a buddy or two that can put out those fires, I don't see anything inherently wrong with the build.
Note: the Adapted shield has a much higher bleed-through rate than the regular Maco, so I think it might be better to run with the MkXII Maco which will also grant you bonus power when being hit (and bonuses to structural and shield skills to boot).