These two suggested games are just loose ideas for historically based games.
The battlefields can be taken from the main Borkowo map. These actions took place on fairly familiar, or at least well-scouted, open terrain, so the players can be shown the a topographic map before the game without any great loss of realism.
After the fall of Borkowo to the Soviets the Polish Siberian Brigade retired to just off the west of my map. Here they were replaced by the "Volunteer" Division, while they moved slightly to the north.
On the morning of the 15th the Volunteers were attacked by the Soviets out of Borkowo, presumably down the main road, with the action mostly an attempted turning movement around the Adamowa to Wola stretch. The Poles were only just able to hold on.
The Volunteer Division had only just days before been formed, out of brand new volunteers as its name suggests. They can therefore be assumed to be extremely green, although totally committed to the Polish cause. Sikorksi gives their numbers as 122 officers, 4,800 bayonets, 275 sabres and 78 MGs but many of these may not have been properly equipped by this stage.
The Soviets must presumably have been part of the 11th RD, perhaps a brigade, as in the main Borkowo scenario.
The Polish 9th ID apparently spent most of the 15th attacking Borkowo from the south. The bulk of the fighting was in the Bledowo area, but eventually the Poles broke through and in the evening retook the bridge at Borkowo (well, the remains of it).
Since the 18th IB had attacked Nasielsk from the south during the night, it seems unlikely it was able to attack 10 kilometres to the west until fairly late in the day. As the Soviets were also attacking the Volunteers to their west, it seems unlikely that they were able to bring all their forces to bear until later either.
Therefore, it seems a reasonable supposition that the initial combats were between the Polish 17th IB and those Soviets not engaged with the Volunteers and this would be my suggested game. The 17th IB was 1,500 to 2,000 bayonets, about 50 MGs, a couple of batteries or so, but effectively no cavalry. Again the Soviets would be a brigade, as in the main Borkowo scenario.
As a pure guess, I wonder if the tide turned in favour of the Poles when the 18th IB turned up. The Soviets may also have had reinforcements, but would presumably already been tired from the morning's battle against the Volunteers.