Is there a phase diagram available for hydrogen fluoride?
Linde Gas contains a vapor pressure curve.  Note that this does not extend to Venusian surface temperatures which are above the critical point.

Hydrogen fluoride may not lift as well as you think.  Its gas phase may associate through hydrogen bonding so molecules could be heavier than just HF.  See the note near the end of the safety information here and note that the association could persist to higher temperature if you apply higher HF pressure than one atmosphere.