Just a thought with the selection of a transformer - ignoring core flux (not realistic, but bear with me) - you can use the typical twin secondaries not so much in parallel, but as two separate supplies. It costs an additional capacitor (though lower capacitance) and an additional rectifier. It means that your copper losses are reduced on individual supplies and regulation is arguably better. It's an approach that I'm trying with my type of machining (typically machining In X/Y, not 3d profiling) - so I intend to bond Y/Z on one supply and X/A on the second - my thoughts are that only one stepper is likely under load at any point in time on any one supply.

80V drivers?, some common ones in this range are AC/DC - if so just remember that the first thing these will do is rectify/smooth the supply internally.

Your preference to rate the caps at 2x VDC - your money. A bit of head-room is a good idea but 2x is a little bit frivolous. Admittedly mine are more so - at 160VDC (50V secondaries) but that's simply because I had them in the shed as part of a bulk-buy.