Even if you are a pro I always say whatever time you think it will take you, add 20% and you will be close to half of what it really takes.

The one thing to be very careful of is your proximity to electrical with the Cat cable.

Sometimes that chain is brass, so take a magnet with you to the big spool o chain and be sure it's got steel in it.

I've got two sizes of chain -- one about 3/32" and one 5/32" or 3/16". I got a little loop for each end, and a small carabiner. The chain hooks to the carabiner so that when you fish down the wall, you don't lose the entire chain if you slip.

Pull strength is not great with either one, but if you can pull and feed... a week ago I pulled in an HDMI, a six-wire 20 gauge ribbon, and composite cable all taped to the larger chain.

To complement this, I have a magnet glued to a 12 foot length of aluminum ground wire, maybe 10 or 8 gauge. It's a truly flexible, medium stiff, repeatable coathanger that can snag that chain from three feet sideways!