Just some thoughts... I don't have experience of using ZorroIII, but I've had network card in A1200 in ZorroII (Hydra Amiganet1.1, 10Mbps) and in PCI (10 and 10/100Mbps Realtek's cards). Max transfer speeds I got with ZorroII were about 600k/s, ~1MB/s with 10Mbps PCI and somewhere around 1.3MB/s with 100Mbps PCI.
About the gfx-card... I wouldn't sell the CVPPC before trying out the Voodoo3. I'd guess there isn't that big speed difference between those afterall, but with V3 you have to use P96 and with CV you can use CGFX. It's a personal opinion which you prefer more, but I myself would like to use CGX rather than P96 and that's why I'd keep CV.
