As an amphetamine maybe at 150 to 250mg if you are lucky (more probably the number is >250mg), but as a PEA very probably not (or at least not bellow 300mg).
If you are going to make it from vanillin than you would better make a longer alkoxy chain instead of methoxy on the position 4. This would at least make it much more probable that you would get an active one. Already 3-MeO-4-EtO-5-Br-PEA has some chances, but if you can put an propyl, isopropyl or allyl there, then you will have considerably more chances. Even a benzyloxy at 4 might give an active compound. These longer chain series might be active at 100 to 200mg in my opinion. As amphetamines they would surely be interesting and up to 2 times more potent, maybe aproaching the potency of the structuraly related MMA and 3-MeO-4-Br-amphetamine, both hallucinogens at bellow 50mg.
There were some bees that were up to these compounds which were given the nickname "haloescalines" at the time, but as far as I know they were never finished and assayed. Except for a single claim at the Hive that 3-MeO-4-OH-5-Br-amphetamine gives some signs of activity at ~5mg, there was nothing else, if I remember correctly. This compound however does not fit into the 5-HT2A ligand SAR, so it was probably a physiological response (3-MeO-4-OH-amphetamine has powerful cardiovascular activity).
The above mentioned "haloescalines" only fit the SAR requirements for psychedelic PEAs when they have a lypophylic chain at position 4 (that is, one that is more lypophylic than MeO).