The longer ATA would be more stable while the shorter ATA might shoot faster. A longer draw will make a more severe string angle at a given axle to axle then a short draw length. Typically, someone with a longer draw will prefer a longer ATA for this reason.
I have a 29.5” DL and shoot a 33” ATA. I would think with your long DL that you would prefer the 34” ATA more, but there is only one way to know. I would go to a shop and try them both out.