Ted R Brown wrote:ACX requires the file measure between -23dB and -18dB RMS and have -3dB peak values and a maximum -60dB noise floor.
Your first post shows RMS = -27.6 dB, which is 4.6 dB below the minimum required by the ACX specification and 9.6 dB below the maximum.
Your first post shows -6.9 dB peak, which is 3.9 dB below the ACK specification.
So what you need to do is to increase the RMS (average) level by around 6 dB while increasing the peak level by (only) 3.9 dB.
Make a backup copy before you proceed.
The simplest way to do that is to first amplify the track with the default settings (up to 0 dB, which in this case will amplify by 6.9 dB) which will bring the RMS level up within range, but your peak level will now be too high, so apply the "Limiter" effect with default settings to bring the peak level down to -3 dB. The default settings for the Limiter can be seen here: http://manual.audacityteam.org/man/limiter.html
If you want the peak level a little under -3 dB (could be a good idea because MP3 encoding is likely to push the peak level a little higher, apply the Amplify effect again with a little negative amplification (say around -0.2 to bring the peak level to -3.2 dB).
Most important: How does that sound?
Ted R Brown wrote:I cannot get sufficient gain to be recording between -23dB and -18dB RMS.
Set your recording level to get a maximum peak level of around -6 dB. If you can't do that then you probably need to get closer to the mic.
-6 dB peak should be close enough to be able to tweak the levels in post production, while still allowing a reasonable safety margin for unexpectedly high peaks that would otherwise ruin the show.