The honest answer that no commercial tutoring site will give you: 11+ practice works much better in short, frequent sessions than in long weekend marathons.
The sweet spot
For most Year-5 children, 20–25 minutes a day, five days a week, is more effective than two-hour Saturday sessions. The brain consolidates new vocabulary and reasoning patterns overnight; spacing the work out gives it time to do that.
Don't skip rest days
One or two clear off days each week actually improve long-term retention. Performance is not linear; rest is part of the process. Practice now for a short session to feel the difference.
The 4-week ramp
Start gentle: 10 minutes a day for the first fortnight. Build to 20 by week four. By week eight, you might add one weekly mock paper. That's plenty.