Oh man, this is exactly my thing. I have tracked charging curves and thermal efficiency for every major MagSafe revision since the A2140. To get this ...
Before I give advice, what apps ur using? Digitizers are kinda picky and I've unfortunately had issues with generic pens. Repairs are pricey so honest...
Seconding the recommendation above! I'd suggest the Sony WF-C700N Digital Noise Cancelling True Wireless Earbuds if you wanna really leverage that LE ...