PYP RTP MTP but how mch fr cost?

1)Solving pyp mtp rtps of costing but how much attempts or years solving is recommended given that costing has repeated questions with values yaha waha karke

2. Last 5 Attempts is sufficient? Upto May 24 / old scheme wale bhi dekh lu kya?

3. how to approach? Chapterwise or full paper wise

4. Chapter wise is much better for now event though whole subject paper practise will be done after every chapter ka revision is done

Pls reply!!!!!