Final phase of preparation tips

Hi everyone,

Long time lurker who has been prepping 1-2hours daily for about two months with MGMAT Books as an Aid, and the OS guide as a question bank, i normally squeeze in 1 heavy day of 4 hours a week and over the last three weeks at least 1 Full CAT in addition to the revision questions.

I'm about 3 weeks away from my expected GMAT exam and I'm in the final "testing phase". I've got some good holiday to revise in the two weeks preceding the exam, unfortunately I've hit a bit of a brick wall in terms of progression on the tests and I'm unsure of how to get the most out of this period.

I'm targeting 720 (Q48/V40) with my main weaknesses being Sentence correction on verbal, my quant errors aren't indicating any specific area of weakness, more a general problem.

My scores are listed below, all tests were taken under test conditions with (Verbal, Quant, IR and AWA). Once completed I review quickly the same day and the following day go into depth on the incorrect q's. The tests were spaced between four and five days apart.

GmatClub1 640 (Q44/V34)
VeritasPrep 690 (Q46/V39)
MGMAT CAT 670 (Q45/V36)
GmatClub2 640 (Q44/V34)

I've looked at my data and although I'm making fewer simple errors in both verbal and quant (no longer making SC/Quant errors at 500 level, greater number of 700 level questions offered by the CAT) and therefore facing a greater number of difficult questions, I'm still not able to capitalise and turn this into muchos puntos!.

SC questions are still nails - I still struggle to conceptualise the grammar beyond 'that doesn't sound right' as such its killing my verbal.
My Quant questions are mainly overlooking key concepts when they're hidden from view... noticing them isn't getting any easier...

Any advice on how to squeeze some development out of these critical weeks would be most welcome!