I think level of practise depends on a) which schools/area you're applying for and b) how well DC can do VR type questions and the speed. This is a personal decision based on your DC and family - there is no right answer. There are plenty of debates about how much is enough/too much for you to read through - lots of food for thought!
We're applying for the N London/Herts superselectives where pass rates for VR/NVR are high 70%s just to get through to second round of maths & english
I've read on other threads that some areas are looking for around 55%.
We went through the Bond books to learn technique, only recently started on full papers - it's important to build up speed as well as accuracy with the pass rates we're aiming at. We haven't done the Bond test papers yet, sorry if I mislead you.
Perhaps you could do a full paper with DC (timed) and see what the score is - that should give you an indication of how much you need to do and what to focus on - speed, eliminating silly mistakes (I think they ALL make these!
), gaps in knowledge ...
Have you looked at the section for your county/area? There will be lots of useful insights in that section relevant to your tests.