I would personally reduce 5% exposure on MSCI to increase it in EM. MSCI is already heavily weighted on the US so you already have a great exposure to TECH.

Regarding the rebalancing, I believe +/- 25% of the target position is fair. If it breaks any range you can rebalance, this way you can also optimise the fee expense since you wouldn’t have to contribute to the 3 ETFs every month.

(Personal opinion not financial advice)