If you use CawaEa today, it only generate one buy signal which was just before the GBP news, I hope you didn't trade that signal. I had used Pipe Surfer Post to determine time interval boundaries (start and end times). At the following pic of my platform and by regarding that buy signal and time interval boundaries (yellow lines) and number of 15m candles you can easily adjust yours CowaEa time inteval
Yes, Begin_Time_M and End_Time_M just are minutes of Begin_Time_H and End_Time_H, respectively. for instance, if begin time for some one be 2:30 then Begin_Time_H=2 and Begin_Time_M=30.
Regarding testing of EA, as I mention because of the nearly every day news and clean break, the result is not reliable but I found if we use TP=2*SL, then during long period it would be profitable.
finally, if you want to change points color, you can easily change the color name, in code of CowaEa lines: 134, 142, 272 and 280 ( ObjectSet(name,OBJPROP_COLOR,MediumBlue) ), by standard color name which you can find them in "MQL4 Reference - Standard constants - Web colors". Also, you can change the size of them at lines:135, 143, 273 and 281 of CowaEa ( ObjectSet(name,OBJPROP_WIDTH,2) ).