Very similar story to yours. Graduated in '08 with a BS in EE. I took and passed the FE in Dec 17, then took and passed PE Power in Oct 18.
Overall, I found Graffeo to be a very good book to study from but ultimately unhelpful in the exam. I probably referenced it for approximately 5 questions (asked the dude next to me and he said it didn't help him much either).
I work with the NEC very often so, even though many of the questions were new to me, knowing where to go was ultimately very helpful.
The NCEES practice exam was also unhelpful. I took it with me and didn't even open it during the exam. I had an old Camara practice test as well (my manager gave it to me) and that was pretty useless.
I took a risk not taking any code books other than the NEC (I had Graffeo, NEC, FE Handbook, NCEES practice exam, & Camara practice exam). We didn't have them in my office and I didn't want to pay for them. I was confident after doing really well on Graffeo, NCEES, and Camara practice tests so I thought I could give up a few questions (big mistake). I came out of the exam feeling like I totally bombed it.
My studying approach was to wake up 2.5 hours earlier every weekday morning (to have 2 hours to study) and to study 6ish/4ish hours on Saturday/Sunday respectively. I can't study at the end of the day (and go to the gym after work). I'm not single but having an amazingly accommodating/encouraging SO was really helpful. Total study time was 4 months.
My test taking approach is pretty simple; I go through and answer all the non-code questions I can (skipping and noting down the code questions and ones I can't immediately solve on the back sheet). Then go through and answer the NEC/Code questions, take a bathroom/water break, then tackle the ones I couldn't get on the first pass.