As it's Magura brakes we're talking about they use mineral oil, not DOT brake fluid.
But you probably won't need to do this anyway - have a look at this
video which explains it better than I could. If you have IS mount brakes then the initial caliper centering will have to be achieved by shimming, between the caliper and the mount, rather than the method shown for post mount brakes.
After that, the pad centering method works just as well with Martas as with Hopes.
Do you have any pad drag at present or are both pads clear of the disc when retracted and do the pads wear "square", or more at the front or back?
You could also try (in addition to centering) cycling the pistons through their full travel a few times - remove the caliper from the frame and take out the pads. Push both pistons as far back into the caliper as they will go and then very slowly
operate the brake lever to push them back out again, all the while checking that both are moving the same amount. If one moves more than the other then hold that one back to force the slow one to move out.
Do not pump the pistons out any further than a 6mm spacer between them will allow(the thick hose cutting guide end of the yellow transport spacer is ideal) and make sure that both pistons move about evenly as otherwise, if one sticks in the retracted position, it is possible to push the other out too far, even with a 6mm spacer in place.