I don't wish to take away from your enthusiasm, but if you're after the experience of contact printing, you might find 4x5 a touch small and 5x7 much better instead. There are quite a few photographers also here on APUG who produce wonderful work with contact printed 4x5 (and also medium format) negatives, but to me the relatively small print size is quite restrictive: composition comes through of course beautifully, but fine detail might be too small for certain viewers.