Bro 23 days are enough to clear second group. but you have to work hard. follow following sch
1st week: 12 hours IDT (service tax would take 3 days, excise 1-2 day, custom 1 day)+ 4 hours 1 chapter of ISCA( 1 day reading 2nd day writing)( 6days)
2nd week: 12 hours DT( You can refer to any book you are following, I prefer T.N.Manorahan book both module and summary book. Leave PGBP+capital gain+ Assesement procedure chapter. rest can be covered in 6 days)+ 4 hours 1 chapter of ISCA daily( 1 day reading 2nd day writing)(6 days)
3rd week:
Day 1-2: Revise IDT(service Tax/Excise +Custom)( 14-16 hours)
Day 3-4: Revise DT( 14-16 hours)
Day 5: Revise ISCA
Days left for costing/OR: 23-6-6-2-2-1=6 days
Day 1-Day3 OR
Day4-Day6 Costing
you can skip writing ISCA subject. or can plan your own schdl. but you will ahave to study for 15-16 hours.
just believe in yourself. you'll be able to do it.
P.S.:- I have cleared second group in almost similiar position. i had got only 15 days leave and i studied for 18 hours. except isca which i studied only before exam day and i scored 55+ marks in each subjects except isca where i scored 47