The vapor port on your solvent tank (recovery tank as you’ve called it. they certainly can be different tanks. in many cases they are the same) is a reasonable place to push from.
You absolutely don’t want to try and get solvent BACK in there with 50PSI of N2 in it.
you can bleed the pressure off IF your solvent tank is below the boiling point of your solvent. Otherwise you’re ALSO blowing off solvent. For pure Butane, that’s around 0C, for pure propane, it’s closer to -45C
Some folks will just bleed it off anyway, venting solvent to atmosphere will cool the tank, and assuming you’re not actively heating it, eventually it will stop venting, and you’ll probably still have solvent in there.
Not a good plan imo, but it IS done.
same goes for anywhere else you choose to bleed off. if your solvent is adding no pressure, because it’s well below it’s boiling point, then almost everything that can be vented will be N2. it will probably still set off your flammable gas detector. I haven’t actually tried setting it on fire.
if you want to force everything into your receiver with N2 (very handy trick), then having your receiver COLD ( ~10C below boiling point of your solvent) will allow you to vent. if your receiver is already warm when the solvent goes in there, then some of the pressure will be hydrocarbons…