Will iTunes Match try to upload all my 6000 songs to my phone?
I have over 6000 songs on/ synced with iTunes match on my computer. If I add my iPhone to iTunes Match will it try to add all those songs to my iPhone?
No, it won't add any, unless you choose to download them. (it will list all 6,000 though, so that you are able to download them as and when you wish)