In a special relationship, you need to determine the needs of your partner, in order to have a successful interaction.
If the seals of the cab windows were replaced with the black u-channel that has the metal inside, you may have to use a less bulky seal, like a rubber/felt seal.
There is little or no physical adjustment that can be done to the cab windows, other than checking that the metal u-channel does not have any 'narrow' places, caused by physical damage.
One place to inspect is on the bottom track at the beginning of the fixed window. I found that with a new seal that space is very narrow and almost locks the sliding window in place.
In time you learn how to effectively interact with your window, pushing little here and wiggling a little there, without ever using force.
More on the coat hanger later.
1994 30' Excella Front Kitchen Trailer
1992 350LE Classic Motorhome