akshay u can go for manish valecha.... the technique to study that book is just read oneby one question as concept are given in question form....and then try to conceptualize it in ur own words.by writing it on a piece of paper....do not lean isca....remember to mark tecnical words....as marks in isca are awarded on tech. words used ..... just try to finish that 3-4 times revision of ur hand written notes....
once u ve written in ur own words and make mnemonics....it will be easier for u to revise it....
paduka would be very bulky....and u will nt be able to revise it from that.....in exam time.....
as far as manish valecha is concerned.. its based on study mat.....
rest u ur ur best judge.....
gud luck
regards
jhanvi