Pocket diapers leaking

So I’m trying to get the hang of this while I’m on maternity leave. Prefolds with covers are going well and don’t leak. However whenever I use a pocket stuffed with one or two inserts they alway leak out the legs. I don’t know how to get the elastic to be tight around the leg enough cause the inserts puff the diaper out bringing the overall diaper away from the body but also I notice it leaks between the elastic and insert cause there’s a small gap. I want to figure this out before I go back to work cause I know my caregivers won’t be able to do prefolds. My LO is 5 weeks. Anyone have suggestions for pocket diapers for 3+ months? Will the fit get better with a bigger child? I have quite a variety bought second hand and I just want to make sure they don’t leak cause today I’ve done 3 outfit changes from pee leaks.