BPM I always seem to halve the actual BPM?

BPM can sometimes be tough because half times are counted on every other DB.
You can change the metronome in preferences if you need to hear extra or less clicks.
TBH, it wont really make a difference unless you are going from 1/8 notes to 1/32 or 1/64 notes.
that's when things can get bunched up and difficult to edit notes. However the PRV grid can always be adjusted for higher resolutions.

I tend to err on the side of the faster BPM. For example I recently had to create a backing track for a client.  (Love Will find a Way/Lion King)  I really felt it as 59 BPM.  When I downloaded the sheet music though in order to save time working out chords etc I noticed it was written at 118 BPM.  So I changed my tempo even before I started.  I am really glad I did though.
 
There are advantages.  The resolution of your DAW midi timing wise is double at the higher BPM.  The PRV view is also much easier to see and edit.  Yes there are double the number of bars but that should not be a big deal.
 
For example in some areas even at 118 BPM there are 4 chord changes in one bar.  That would have been 4 chord changes in half a bar at 59 BPM.  Which would have been more of a nightmare.  At 118 as well the Precount is twice as fast so you are getting into record mode in half the time.  A big time saver when you are dropping in a lot etc...