Hi REB

Venus needs its excess nitrogen to lower the mixing ratio of water vapour. Slows the drying out process that baked its crust hard so long ago.

I imagine the highlands in Venus' temperate regions will be reasonable, and hopefully lots of bright, salty equatorial lakes and salt-pans to bounce heat away. If the rotation - after carefully arranged infall of all that hydrogen - is still slow a thicker atmosphere will help distribute heat. But I can imagine a continual cloud cover the sub-solar point from evaporation and low Coriolis forces. Or maybe complex ocean currents if there is a continuous cover from the water - wonder what the porosity of Venus' regolith is like. Also hydration of so many anhydrous minerals will soak up a good fraction... albeit slowly.

Finally: Does Mars really need Earth amounts of N2?

Adam