Changing Unit Weapons and Stats

[President]

I had some simple questions:

1) How do you change a unit's weapon/type? For example, I am trying to change Numidian Skirmisher's melee weapon from a spear to a knife, yet when I change the tech type in the expor_descr_unit txt file it does nothing, although I do believe it does change it "physically," though not visually... this is what I've done to the descr txt file:

;219
type african skirmisher javelinmen
dictionary african_skirmisher_javelinmen ; Numidian Javelinmen
category infantry
class missile
voice_type Medium_1
soldier african_missile_numidianjavelinman, 50, 0, 0.9
mount_effect elephant +2, chariot +4, horse -2
attributes sea_faring, hide_improved_forest, can_sap, very_hardy, hide_long_grass
formation 1.6, 2, 3.2, 4, 6, square
stat_health 1, 1
stat_pri 6, 2, javelin, 60.5, 6, thrown, simple, piercing, spear, 10 ,1
stat_pri_attr thrown, ap
stat_sec 7, 2, no, 0, 0, melee, blade, piercing, knife, 0 ,0.04
stat_sec_attr no
stat_pri_armour 1, 9, 2, flesh
stat_sec_armour 0, 0, flesh
stat_heat -1
stat_ground 0, 0, 1, -1
stat_mental 10, normal, untrained
stat_charge_dist 30
stat_fire_delay 0
stat_food 60, 300
stat_cost 1, 987, 247, 20, 30, 987
ownership egypt, seleucid, slave

*I've noticed there is no space after the coma, before the lethality value...

2) Would changing the stats this way cause any CTDs? Also, is the stat_heat value really inverted?