Win32 import batchsize tweaks
Win32 import batchsize tweaks

Reduce frequency of resizes: bump minimum increase from 128MB to 512MB
Use a bigger safety margin at small batch sizes

eiabea/bitmonero,ranok/bitmonero,ranok/bitmonero,eiabea/bitmonero,eiabea/bitmonero,eiabea/bitmonero,ranok/bitmonero,ranok/bitmonero,ranok/bitmonero,eiabea/bitmonero,ranok/bitmonero,eiabea/bitmonero