I have been experimenting with the same issue as above ongoing for several months. jointennas as traps, special made traps, various preamps and distribution amps.
but first, the general sign of overload is signal strength going down as you point towards the tower and going higher as you point away and signal level going down various amounts on different channels.
I have an issue where ch 24/25 interferes with ch14 which is of lower power in an amplified setup. when ch 24/25 goes off the air the issue on 14 goes away. the interference also affects others channels in the uhf spectrum and mostly weak/low power...ch 22, 35,40,60 come to mind.
-traps did not help the situation. there were too many points of interfering channel ingress and could not filter every point.
-lower gain high output preamp helped the situation (hdp-269)
-bypassing vhf, fm, and only amplifying uhf also helped.
-just ordered a uhf band pass filter and will place it before the hdp 269 to see if it helps the situation.
the issue is most likely over amplification worsening the effects of co channel interferences.
trapping will not necessarily improve the situation as you like and would be trial and error.
I am still intersted in entertaining ideas on improving signal strength, as sometimes during bad weather my signals drop down in the 60's where it pixelates and loses signal.
my suggestion would be using an hdp 269 preamp of lower gain and high overload tolerance amplifying uhf and passing vhf/fm. the ap4700 may be ok but the unit has higher gain and would be a risk. I tried the ap 4700 here and had to punt and go back to the hdp269 and amplifying only uhf.