How do I "mix" captured Hi8 footage with DV footage on my Mac?

I'm going to enter a short film about China at a local film festival. I have both DV and Hi8 footage, which I'll capture to my Mac. The DV footage is captured through firewire, the Hi8 through an ATI card (S-video). The plan is to edit it all together on the Mac, ready for export back to a DV cam or transfer to cine film (? Is that possible?).
What is the minimum resolution I need to capture it at, to keep a quality that can be projected onto a large screen at the movie theater ? 640x480 or 720x486 or something else ? I can't find this information anywhere.

I heard that DV is "500 lines" while S-Video/Hi8 has "425 lines". How can I practically use this information. I guess I need to "upsample" the Hi8 footage to 500 lines before I can mix it with the DV footage? Which software will do that for me on my Mac running under Os9?. And to which format should I convert it to, so that it will "become" DV footage (even though I realise it will be noisy)?

Thanks in advance
Marty

 

If you are working in NTSC then your DV AVI footage is Captured at Full D1 Resolution which is 720+480 so you would have to capture your Hi8 Footage at the same resolution if you want to Mix them on the Timeline ....If your DV Camcorder has Analogue Inputs then you can use your Camcorder to Capture the Hi8 Material directly to your PC in DV AVI format and the Quality would be better than if you Captured useing your ATI Card....
After editing you can Output your Project Back to DV tape or you could render your project as a Mpeg2 file and Author it to DVD.....

Cheers