Hello Rich,
I hope you are doing well.
I just bought ETS set of books (OG + additional verbal and quant reasoning books).
I understood from comments here and there that these new 300 question set was closer to real test difficulty.
A friend of mine gave me his multiple books of Manhattan GRE (bit old, 2nd edition, but I guess it can not hurt) plus a print out of Nova quant, guessing it should be enough.
Once studying for GMAT I think I made this mistake to overprep with too much heterogeneous material : Kaplan, OG, Princeton, GmatClub and many many more.
What I noticed is that having had some private coaching sessions for gmat verbal, it helped me to move to the next step though it never translated into the 750 score I was targetting.
Thus in terms of methodology I was thinking about working on my own for lets say 6 to 8 weeks to better identify my weaknesses and also learning additional vocabulary.
Then maybe going for a
Magoosh type of prep over a month and see where I am after these 3 months.