What size nest box is best for them. There seems to be several sizes for sale or will they nest in any small size (say 100x100x150) & will any finch build in a box if no other option is available.
Different finches have different nesting requirements, Gouldian's nest in nest boxes, other finches build their own nests in nesting places that you have set up in your aviary, example tea tree bush
If you tell us what you will be getting we can better advise. I have 4 mixed avairys so use a wide mix of nests. From a small gourd like nest my daughter wove in the aboriginal basket making style which is no bigger than my 2 hands with fingers touching to a 20cm cubed wooden box with a 5cm square hole in one corner for entry. But I have a mix from orange breasteds to Javas. Not in the same avairy. I find variety of nests and locations works best.
LML
Other than Gouldians, most native finches prefer to build their own nests in vegetation. I suggest you cut some dense branches and put bunches of them at various heights in the most sheltered part of your aviary + supply plenty of grasses for nesting material.
Thanks Nat&Glenn, my b/day was August but didn't have the aviary finished, they got me pair sydney w/bills (already have 2 pr o/breast & p/heads) & another pair of canaries for my other aviary
