Here's my opinion.
Work up to chopping a '49 Ford as it's one of the hardest to do......correctly. Steve got it right! That takes a lot of strategizing and experience to pull off.
Start with an early car (Model A, '34 Ford pickup, '32 Ford Sedan). Something with almost, if not absolutely upright pillars. Then work your way to a mid-fifties pickup ('50 Ford, '56 Ford, '55 Chevy) and then go to a car with skinny sloped A and C pillars ('55-'57 Chevy or Ford, '58 Plymouth Belvedere) and then lastly....I would do a 2-door coupe with the slanted pillars and the wide C pillar. I just feel like otherwise, it would be too easy to lose interest and ambition and it will end up in the parts pile. If you've never chopped a top, take baby steps.
If you're hellbent on this being your first chop, it might not hurt to go ahead and buy the Jimmy Flinstone car just to have beside you for reference. Just a thought.