Robert,
great info, as usual. Regarding the composition of the screening rearguard force during the clash at Nasielsk, general Friant, in his report to Davout, wrote that his troops were opposed by five Russian pieces, so, probably, there was a half-battery (minus one gun) with the rearguard.
I wonder whether the two battalions (fusiliers?) from the Pavlovskii Grenaderskii Polk that covered the earlier withdraval remained in the rearguard or not.
Speaking of Dorokhov force, in your article about the engagement at Borkowo you estimate the strength of the hussars at (about) 120 men per squadron. Since the average Russian squadron (as per Bennigsen's memories) numbered about 90 troopers at the time, I wonder whether light cavalry fared better than cuirassiers and dragoons in "retaining" their strength.

Kind regards,

Amedeo