Strength will be useful for carrying pots because do not always rely on heal. 30 strength is alright.
I would advise against having vitality that high. It is way better to go for high dex ( cast time is calculated by : DEX / 1.5 , courtesy of
http://rodatazone.simgaming.net/mechanics/stats.php ) . The reasons are:
a) GC will always reduce your hp by 20% due to kickback. The higher your HP , i.e. VIT, the more SP you will have to use to heal yourself.
b) high dex = faster gc cast = kill faster = better survival rate
Holy armor is not easy to get and you can only get that by two ways:
1) angeling card ( good luck with the OCAs or repetitively killing angeling)
2) B.S.S skill which is done by 1 priest and 2 acos.
A more realistic gear setup would involve balancing DEF and MDEF. I would recommend the following;
double hurricane haedonggum
poo poo hat/ beret/ feather hat/ angel halo / wedding veil
cranial mirror shield
rosaries/safety rings/ anything to increase MDEF
ragamuffin mant / immune garment
crystal pumps/ any carded boots
Regarding Magnum break, leave it at level 1 because when there are too many monsters piled up on 1 cell, the number of gc hits will reduce. For example, 3 monsters stacked on 1 cell = all monsters will only get hit once. 2 monsters stacked 1 cell = 1 monster will get hit once and the other will get hit twice. Magnum break will help disperse the stacking and hopefully render 3 hits to all victims.
My last advice would be, time your GC cast proportionately to the speed of your incoming target. If done correctly, you can hit your target 4 times. It is a known glitch. Practice the 4 hit GC on khalitzburgs.
Feel free to ask anymore questions.