"Balancing" a single cylinder two stroke may require mystical formulas and an alchemist's lab - but on the other hand have you considered the basics? These lil motors respond really well to even such simple things as a good port & polish, an expansion chamber, a better carb than stock, replacing the head and making your own intake manifold.
Though many consider these "performance" upgrades it's true that much of it in reality is just "correcting" the sloppiness inherent in such low-cost, low quality Chinese engines. It's really not difficult in the slightest, ranges in cost from nothin' but your time to a maximum of about $200 - if you choose the absolutely nicest of aftermarket carbs and expansion chambers.
Beyond the above? Much as I hate to say it as I'm guilty of being a borderline fanatic... it may simply not be worth the effort (beyond amusement ofc) as engines like the Morini are available. Starting out far better "balanced" than our poor lil HTs they may be worth considering if that's your goal.
The reason there's no comprehensive "step by step guide on disassembly" of the engine is that it's so basic as to be four nuts to remove the top end - the rest not needing to be addressed as there's little to be done. A Dremel the fanciest tool ya need, patience the scarcest commodity - most if not all the information you desire to be found here on the forum.
Of course we'll be more than happy to address any specific questions ya have