i know this is gonna sound really strange but the only time i really solo anything is when i am editing.
almost never when i am mixing.
that's not how people listen to music. also, you are trying to mix a track so that it fits into the mix properly, and how can that really be done unless you are listening to the entire song?
i think there are cases where soloing a track is useful for automation purposes or for crucial mixing decisions or possibly soloing drums to make sure there is no comb filtering.
so, i guess that is my advice to you... stop soloing shit and mix the song in several passes.
also, if you spend more than 30 minutes on a mix you probably won't get it where you want it (imo). i think after hearing the song so many times you become desensitized to all of the potential disparities and eventually don't hear them at all. it happens to even the most successful engineers.
