this doesn't need src modification
you can just edit the maya card at item database
4146,Maya_Card,Maya Card,6,20,,10,,,,,,,,32,,,,,{ bonus bMagicDamageReturn,50; },{},{}
maya card reflects 50% of the magic damage you received but also considering the mdef of the receiver so its really depends on many factors
so if you want it to reflect a constant 1k damage then you'll need yeah a src modification for that but it would take long and prolly would need a paid service for it
bonus bMagicDamageReturn,50; ----> dude its not 50% reflected magic damage it is a 50% Chance to reflect the magic damage
oh my bad
well it would need a lot of work to implement
why don't you just increase your mdef or use gtb card