Avoid frozen fruit.
You can use other fresh berries you prefer, such as blueberries, blackberries, gooseberries, strawberries or mulberries. But do remember to do your own macro re-calculations. You can even use other fruit, providing it fits your macros.

Either freeze for just long enough to give you a semi-frozen consistency, or leave to harden like creamy lollies.

Metric kitchen scales are an inexpensive yet invaluable gadget to ensure accurate measurement of ingredients. Store them upright in a cupboard or over your worktop and they'll only take up a tiny bit of space. Click HERE for the ones I use. For U.S. option click HERE.