The cost per bit is a doubling in time. So factoring a 512 RSA, compared to a 1024 RSA is significantly cheaper. The OP used contemporary hardware to do this. so, we'd have to ask if the orders of magnitude improvement in tech (QC aside) would permit 1024 in tractable time. I tend to no, but I appreciate there are other points of view. And of course, the belief that one day we can apply Shor with success exists. At which point the question is moot. Not that Shor does not itself demand significantly more stable gates, per extra bit of RSA. I always wonder why people don't look at the trend line in stable QuBits and the trendline in cost of RSA. Do the lines intersect?

Remember, Shor is like a coded gate level algorithm expressed as sequences of interconnected stable QuBits. So, if you double the cost for each RSA bit you add, its not "nothing" in terms of how you wire the rig.

(not a cryptographer, or a QC person so I expect to be hit by a very cold clue-by-four shortly)