Method to Acquire - On Chapter 9, go to either the right house in the northeast, the left house in the northeast or neither. If you want a stronger Gonzales, go to the left house in the northeast or neither. He'll show up as an enemy on Chapter 10 if you go to the left house or neither and on Chapter 11 if you go to the right house. Speak to him with Lilina to recruit him.
Damage - Gonzales will be dealing lots of damage as he maxes strength exceptionally fast. His strength gains are like Lilina's magic gains. Except that they are 15% lower.
Critical - As a Berserker, he gets a 30% critical bonus and with some supports, he can go higher then that. Unfortunately, his low skill doesn't add much to his critical.
Dodge - He's alright at dodging. He averages 65 if you go to the right house and 73 if you go to the left house or neither in the northeast of Chapter 9.
Growth Rates
HP - 90%
Strength - 60%
Skill - 15%
Speed - 50%
Defense - 25%
Resistence - 5%
Luck - 35%
Average Level 20 Berserker Gonzales(left house visited or neither on Chapter 9, Hard Mode stats in parenthesis)
HP - 60(60)
Strength - 30(30)
Skill - 15(18)
Speed - 28(28)
Defense - 18(18)
Resistence - 2(3)
Luck - 17(19)
Total - 170(176)
The reason his Defense has no change is because he does not gain any defense with his Hard Mode bonus.
Average Level 20 Berserker Gonzales(right house visited on Chapter 9)
HP - 60(60)
Strength - 30(30)
Skill - 14(16)
Speed - 25(27)
Defense - 16(18)
Resistence - 1(2)
Luck - 15(16)
Total - 161(169)
Supports
Lilina - 15/30/40 turns
Echidna - 59/60/80 turns
Dayan - 59/60/80 turns
Treck - 59/60/80 turns
Garret - 40/60/80 turns
Bartre - 59/60/80 turns
Rating - 8.65/10. He's a good Berserker, definetely better then Garret, but he has very bad accuracy and if he goes anywhere near a magic unit he'll take full damage to their attack unless you are playing in Hard Mode because he will start with 1 Resistence if you are. Still, he shouldn't be brought near them.