Which nappy inserts to choose?

Inserts and boosters for all ages great as you can split for twice as many inserts while bubs is younger;
Heavy Wetters and Overnights ideally should only be used when bubs has maximum one rise snap done up so from ages 6months and over but definitely a must have in the arsenal;
Small/Medium prefolds go in all OSFM nappies, the larger ones can become more difficult to stuff. as they require folds in both directions;
Snakers for the trimmest options!

Absorbency is highly correlated with weight, although there are key properties to be aware of and their benefits:

Microfiber: absorbs fastest but has compression leaks, wrinkles the least, best for flooding during teething and toilet training
Bamboo: a good all rounder for absorbency especially when paired with the microfiber to catch the compression leaks
Hemp: more absorbent than above, drys harder, wrinkles the most, shrinks a little, better when paired with a non shrinking fabric such as bamboo

Weight chart below:

B/M 4 layer insert and booster: 101g
H/B 4 layer insert and booster: 100g
Snaker 0+ 4 Layer Bamboo: 65g
Snaker II 6M+ 5 Layer Bamboo: 111g
PETITES/TRIMS 5 Layer Bamboo: 103g
Heavy Wetter 5 layer Hemp Insert: 101g
Overnights - 4 Layer Hemp Insert + Staydry + 4 Layer Hemp Booster: 140g