If you havent already, teach yourself what the basket of holdings are and how to read them. By owning the S&P and also QQQM, you are probably already overweight big tech.
That being said, the next step is to pick a number (I use 5%) as the max weight a stock can have in my portfolio. For overweight I use 7-8%.
Then build a little chart in excel to track each individual holding (in the basket of holdings and individual stocks) to track sector weighting. Then have excel calculate the weight of each stock. Example. if AAPL is 5% of the S&P index and you own $100,000 of the S&P index then you technically own $5,000 in AAPL. If its 10% of QQQM and you own $50,000 of QQQM you own another $10,000 of AAPL. If you have $25,000 in IXUS then your total portfolio is $175,000 and $20,000 of it is AAPL. So AAPL is 11.4% of your total portfolio and you haven't bought a single share of AAPL yet.
Its pretty critical to understand basket weights when you are dealing with big tech and how much they influence the indexes because of their market cap. Below is an old version of what I am talking about to track sector weighting.
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To check individual weighting:
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