Bass in progression

Select a chord and press 1 to get a root chord

( can't exactly remember what chords only mode stands for )---> as i suggested earlier perhaps a menu line with explanation of the function in the GUI of Synfire could help.
It is impossible to memorize all those undocumented functions + documented functions  

I must say i am little bit depressed for a while from Synfire, because some base functionality is too much hidden in the program.
A good example is for 'painting symbols'  ..use in the Transform menu : uncheck draw repetitions.. now you with the pencil draw in the phrase editor symbols with a choosen length.

Use the + and - buttons to alter the bass. Hold ALT to apply chromatic steps.

Use Transform >> Reset Inversion to delete the bass setting. This will select a bass automatically.

All this is not "hidden", by the way.

Well.. for "Reset Inversion"--> it should be better to use : Reset Chord Inversion

Draw Repetition --> Draw Symbol Repetition that is more clear now we know where we talking about.

Octave doubling ... it should be handy if there was one command for a root chord bass doubling for instance.
Accoording the doubling rules for triads, because not all chord notes in the triad can be used for doubling as i understand

a book source: (music theory for computer musicians

Writing a minor chord effectively for these forces would necessitate the use of far more than three notes. To solve this problem, certain notes are doubled at the octave. The best notes to double tend to be the root and fifth because these give the chord its identity and backbone. Through octave doubling

It seems that the root and fifth note can be used .. so one command for this instead of + and - to position the note under the triad.
With this you can override(overrule ? ) in the progressioneditor the Synfire magic AI 

Octave of the bass is controlled by the lower playing range of the global "Bass" instrument. You can set this on Audio & MIDi Setup window on "Global Instruments" tab.

Progressions are instructions & rules for all instruments. Individual instruments decide how to interpret them, hence this extra step.

I absolutely understand that. LE users want a single instrument and arrange a single track of physical chords only.

The extra hoop of keeping multiple instruments in mind when designing a progression, like with Synfire, is confusing and unnecessary. This is an undesired side effect of the powerful prototyping technology being stripped down to meet the basic needs of a "chorder".

We will eventually hide this generality behind a more simple user interface, so the user can make the adjustments as if it was a single instrument only.