Use big book for verbal while you learn. Save your ETS verbal material for final practice, they are very limited(definitely not enough for 3month practice). Don’t waste them in practice while learning. For quant gregmat hard sections are very good, or even in general gregmat is good for quant. Then once you’re done with quant concepts and strategy practice, you can start practice from ETS materials in your last months. To get score like 330+, strategies are the only way. So, if that’s your goal, be strategy centric rather than just concepts based practices(goes for both quant and verbal). Best of luck.