Basically on a baby mag the lowest you can raise in DEF is +5 per single item (as shown on feeding charts) via Monomate/monfluid/antidote/antipara. If you Bank the mag after EVERY item the +5 will round down to +4 thus less defense increases as you lvl. You can do this on any increase of DEF, not just the baby (so for 187 POW you'd just continue to 35-50). It can be long a tedious, but since this server has infinite mag feed it's not so bad. Other servers you'd have to wait 3.30 each item you fed then banked mag. This is the bank trick.
Using this method is how I got my 0DFP mag to remain 0DFP upon evolution. (without doing so it would always gain 1DFP): Picture below~
This example was using antidote but it would work the same as long as the 4 specified, just other stats.
@thelionorion it does work here, I did it here~