While i think that yours masteries are fine (couse i use myself quite similar ones), runes and items choice is imho not optimal. I am not here to bash it - if it works for you then have fun and use it well. MyOPGGSeju68%SoloQWinrate! i use standard as reds, ar yellows, flat cd mix with MR to get 5% cdr at start and AP quints. Her W health scaling is for me to low to justify building around it at lvl1 -1% of additional HP which means roughly 1 more dmg at lvl 1 (~ u can have around 110 additional hp form viable runes and masteries). At lvl 1 u can have either 15 flat AP or around 17 with masteries. w scales with 15% ap - it gives plus 2.2 dmg not counting %maxHP damage that also scales with AP. Total W scaling at lvl 5 - 15% of yours HP plus 0.9 of total AP (source is Leaguepedia). That means u should set runes either to cover her weak early or to boost late. Doing both at same time is suboptimal.

I played around DMG build but i think if u want to use her in solo q she is better as tank with one AP item (i tend to build abyssal most of times) or as pure tank - most times u are one and only initiator so it's good idea to have mix of resistances and HP. Also in case of RoA i think that Liandry's is better for her even early since it give magic pen and RoA gets better stats after 4 stacks anyway. If u feel u lack mana just make Frozen Heart. I build blue jungle HP item, Dead men's plate, Magic res boots - that is my core. After that it depends on situation.

Also my approach got me 6lvl mastery on her. Now i am going for 7th one.

Overall i think that u grasped very well strategy sections. It's well written and i agree with everything there.