[2E AD&D] Elf Mage/Thief Spelljack Kit

So weird thing here, I'm actually playing in the first 2E Advanced Dungeons & Dragons campaign I've played in, in like, 25 years. I am having a good time playing an elf mage/thief named Indel Silverleaf. 

However, I note that the only kit for elf mage/thieves is the "Spellfilcher" (such an... unfortunate name) which kind of sucks. 

So, I've made an equally poorly named kit, the Spelljack, and am awaiting DM approval. 

It has been so long since I've played 2E I've no idea if it is properly "balanced" or not. Those of you who play 2E please let me know...

Spelljack Kit

An Elven Mage/Thief Kit

Bonus Weapon Proficiencies: Dagger.

Bonus Non-Weapon Proficiencies: Appraising, Reading/Writing, Spellcraft.

Arcane Trapmaster. Unlike normal thieves, your magical talent allows you to use your full find and remove traps skills on magical traps; these skills are not halved for you when you are looking for or disarming magical traps.

These can be trap-like spells (such as explosive runes, fire trap, and so forth) and more esoteric traps that have magical aspects or deal magical damage.

Additionally, you can increase the chance to find a magical trap, and if found remove the magical trap, by expending a memorized spell. You add 10% to your chance of success at each for every level of the expended spell (the bonus applies to both find and remove the same trap).

Spellblade. You are able to enchant a dagger into a spellblade. This requires one hour and the expenditure of 50 gp of magical unguents, oils, and reagents for every level of experience you possess as a mage. You can use the spellblade to spelljack spells from spellcasters (see below).

The spellblade also counts as a magical weapon for purposes of hitting monsters that require a magical weapon to hit but has no bonuses (you can enchant a magical dagger as your spellblade).

Your spellblade loses this enchantment if you roll a Natural 1 on your saving throw when you make a spelljack attempt; if you roll a Natural 1 on an attack against a creature that requires a magic weapon to hit; if it is subjected to a dispel magic or antimagic field; or if another spellcaster takes the spellblade and holds it for more than 10 minutes.

You begin play with a spellblade already enchanted. You cannot have more than one spellblade enchanted at a time.

Spelljack. You can attempt to siphon a spell away from your target and use it for yourself.

When you hit a spellcasting target with a successful attack with your spellblade, you can choose to forgo dealing damage in order to attempt to steal a memorized spell from the target.

Spelljack has no effect on innate spell-like abilities.

You can choose which spell to steal if you know that the spellcaster has it memorized; otherwise, the DM determines the stolen spell randomly.

You can automatically steal a spell of a level you can cast.

You can attempt to steal a spell of a higher level with a successful saving throw versus Spells, with a penalty equal to the level of the spell. If you roll a Natural 1 on this saving throw, you suffer 1d6 points of damage per level of the spell you attempted to steal via internalization of the magic.

The target of a successful spelljack attack loses the spell from memory; they can memorize the spell and use the spellcasting slot as normal after the usual amount of rest.

You retain a spelljacked spell in your memory for up to 1 hour per level; you can cast the spell once. Once the spell has been cast or the time expires, the spell fades from your memory. You cannot add a spelljacked spell to your spellbook nor scribe it onto a scroll.

At any one time, you can possess a maximum number of stolen spell levels equal to your class level. For instance, at 4th level you can have two stolen 2nd-level spells, or one 2nd-level spell and two 1st-level spells, or any other combination of spells totaling four levels. If you steal a spell that would exceed this limit, you must choose to lose stolen spells sufficient to reduce the total number of stolen spell levels to no more than your maximum.

If your maximum number of stolen spell levels is less than the level of the spell you just stole, you suffer damage from the spell as though you had rolled a Natural 1 on your save, as above.

Spontaneous Casting. You can expend a memorized spell to cast a detect magic or read magic spell. The spell is cast at your level as a mage. You gain no additional benefit if you expend a 2^nd level or higher spell to cast the spell.

Oh... and yes, my character is modeled after this Indel...