Hugo,
let me try this again, my first reply got deleted cause my picture attachment was too large.................
things to consider when using the highest power:
The Duty Cycle of transmission at +20dBm is limited to 1%, with a maximum VSWR of 3:1 at antenna port, over the
standard operating range [-40;+85°C].
if you were to upload a sketch could you damage the chip?
I found my range suffered when i tried power level 31, not so much on the default bitrate, more so at slower bitrates. I don't have a power meter to measure the output, but maybe the slower bitrates are over driving the PA.
Would you rather have a cleaner signal at a lower power, then a stronger, possible dirtier signal?
for instance, turning the volume on a television to 100% seldom makes the audio sounds better...
What kind of antenna is the 5.5 dB your using?
I found all of those cheap ebay 433 MHz antennas were junk for long range, even though the SWR looked good on my sweep generator, their performance was poor.
Those bare "spring" antennas were ok. if you just don't have the space.
Philip