Hi Lise and welcome to the Tree
Even just using one reusable nappy a day is an excellent way of starting out, and will still make a difference to landfill (even more so when you go cloth full time)
For heavy wetters you need to focus on the absorbant materials of the nappy, so think about bamboo, hemp and zorb. Microfibres absorb quickly, but don't hold anywhere near as much liquid and you can get compression leaking.
I think the tots bots bamboozle stretches come with a small booster. You might also need more boosting between the nappy and the wrap to get through the night.
Otherwise at this age, I'd suggest using a dedicated night nappy, such as the Holden's Landing Bedbugs (HLBB) or Weenotions night nappy (WNNN).
Other people will be able to tell you how wool or fleece covers might be able to help at night but I don't have any experience of those.