Someone like Rotgiers de Gerberoy (The Lion and the Lily p.60f) might be what you go for: as a fighter and a magus, he needs to understand well when to use which skill or spell.
But Rotgiers is a over 50 years out of gauntlet. He started as a Large Rego Terram Tremere with Improved Characteristics, Gentle Gift and Puissant Single Weapon, and needed lots of xp to become what he is. House Tremere might have helped and even made him.
Here is a young fighter magus example: a Muto Flambeau.
Cornix
Covenant: Triamore
Characteristics: Int +2 (Shrewd), Per -2 (Focused), Pre +1 (Fatal Beauty), Com 0, Str +3 (Stalwart), Sta +1 (Tough), Dex +1 (Deft), Qik +1 (Nimble)
Size: 0
Age: 21 (21), Height: 168 cm, Weight: 58 kg, Gender: Female
Decrepitude: 0
Warping Score: 0 (0)
Confidence: 1 (3)
Virtues and Flaws: Hermetic Magus, Gentle Gift, Affinity with Single Weapon, Improved Characteristics, Tough (Soak: +3), Warrior (50/50)*, Puissant Single Weapon, Deft Form (Corpus) [Form: Corpus], Affinity with Muto, Minor Magical Focus (self-transformation), Knight, School of Ramius, The Gift;
Rigid Magic, Envied Beauty, Bound Magic, Unimaginative Learner (Studying from Raw Vis: -3), Higher Purpose (Code of Garus), Miles
Personality Traits: Brave +2, Chivalrous +2, Confident +2
Reputations: Flambeau House Acclaim (Magi Flambeaux) 1
Combat:
Dodge: Init: +1, Attack --, Defense +4, Damage --
Fist: Init: +1, Attack +4, Defense +4, Damage +3
Kick: Init: +0, Attack +4, Defense +3, Damage +6
Dagger: Init: +1, Attack +7, Defense +5, Damage +6
Sword, Long & Shield, Heater (AoUW: +1): Init: +3, Attack +13, Defense +14, Damage +9
Sword, Long: Init: +3, Attack +13, Defense +10, Damage +9
Lance & Shield, Heater (AoUW: +1) (mounted): Init: +2, Attack +15, Defense +15, Damage +8
Hammer & Shield, Heater (AoUW: +1): Init: +1, Attack +11, Defense +12, Damage +11
Soak: +17
Fatigue levels: OK, 0, -1, -3, -5, Unconscious
Wound Penalties: -1 (1-5), -3 (6-10), -5 (11-15), Incapacitated (16-20), Dead (21+)
Abilities: Latin 4 (Hermetic Usage), Artes Liberales 1 (Grammar), Code of Hermes 1 (Wizard's Marches), Magic Theory 3 (Invent Spells), Parma Magica 1 (Mentem), Concentration 1 (Casting Spells), Etiquette 0 (Magi) (1), Charm 1 (First Impressions), Awareness 1 (Keeping Watch), Survival 0 (Woods) (1), Athletics 1 (Jump), Brawl 3 (Dagger), Animal Handling 1 (Horses), Low German 5 (Saxon), Order of Hermes Lore 1 (Flambeau), Ride 3 (battle), Scribe 0 (Copying) (1), Single Weapon 5+2 (Sword, Long)
Arts: Cr 0, In 5, Mu 12, Pe 0, Re 0, An 5, Aq 0, Au 0, Co 5, He 5, Ig 0, Im 0, Me 0, Te 5, Vi 0
Equipment: Shield, Heater (AoUW: +1) (Init: 0; Atk: 0; Dfn: +4; Str: 0; Cost: Standard); Full Plate and Mail Armor (HoA: +2)
with Open Helmet (Soak: 17) (Soak: 17; Protection: 13); Horse: Warhorse (Mounted Combat)
Encumbrance: 0 (3)
Spells Known:
Shriek of the Impending Shafts (InHe 15) +11
Cloak of Black Feathers (MuCo(An) 30) +23
Disguise of Own New Body (MuCo 5) +23
Eyes of the Cat (MuCo(An) 5) +18
Gift of the Bear's Fortitude (MuCo 25) +23
Aegis of Unbreakable Wood (MuHe 15) +18
Hardness of Adamantine (MuTe 25) +18