From what I have read 16w will produce 100db for 88db speakers.
16 watts is 12 db greater than 1 watt, and 88 + 12 equals the 100 db figure you cited. However that is at a distance of 1 meter, and that assumes the 88 db spec is accurate, which as I mentioned it is not.
To get a better handle on that, I suggest using the following calculator, plugging in your listening distance, speaker placement, and using 85.4 db for the speaker’s sensitivity:
https://myhometheater.homestead.com/splcalculator.html
For example, based on 16 watts, 85.4 db, a 10 foot listening distance, two speakers, and speaker placement within 2 to 4 feet of the walls the result is a maximum SPL at the listening position of 93.8 db. And only 90.8 db for speaker placement further away from the walls.
Also, as I indicated the speaker’s impedance rises to very high levels at various frequencies (42 ohms in the vicinity of 2 kHz, more than 20 ohms in much of the upper midrange and lower treble, and 32 ohms at about 85 Hz), and comparing the 8 ohm and 4 ohm power capabilities of the F6 and SIT-3 suggests that they will not be able to supply much power into those high impedances. That will be compensated for to a significant degree by the speaker’s presumably greater efficiency at those frequencies, but still ....
Regards,
-- Al