Convert my '74 or sell it all and buy a '70?
How much do you enjoy or hate doing major body work? A cloning isn't that major - just swapping parts. Rear quarter work is major.
How much time do you have for it?
Do you have the garage space?
Will your wife help or hound you about how long its taking?
I would scout around a little, post a notice here to see if a sweet deal on a 70 -72 pops up. Those cars are harder to come by but prices are way down and you never know. I think someone from Nevada had a roller here a bit ago and could not get a bite. Set a time interval and if nothing comes up, do a clone project. I'm doing a Demon clone, including a frame swap partly because I like the challenge.
Nobody can say what resale will be except nothing great in the near future.