IMO, you shouldn't be a "Tank Veigar" main. Rather, you should build items depending on what your lane match up is and how the game is progressing. Basically, tank veigar or straight damage veigar is generally going to be the same at the 5-items (Sorc boots + Morello's + Deathcap + Void + Defensive item). It's all about what order they come in.
You pretty much always rush Lost Chapter for the mana sustain. From here, you make your first decision. Need to dodge skillshots (Anivia, Syndra, Xerath, etc.) buy boots. Otherwise go for morello completion.
When you hit 6, if you can kill your lane opponent, focus on finishing morellos. If you can get a good roam (usually bot lane), rush complete sorc shoes first. Don't tabis... You need the movespeed to get picks/run away from ganks/to roam, but you don't yet have the hp pool yet to where additional armor makes sense and you shouldn't be getting harassed by auto attacks since most AD midlaners are AD spellcasters. Only reason to go tabis is if it's lucian mid or something stupid like that.
Once you have Sorc + Morello's, if you are stomping and have a ton of gold (from multiple kills or turrets), rushing Deathcap next is ok. If you are against AP (especially AP assassin), going banshee's second is really good (more effective than abyssal) – this should be your default second item since CDR is super good and most of your opponents are going to be AP mid laners. If you are against AD mid laner, buying a chain vest next and going deadman's next is ok.
As far as high elo viegar mains, well there really aren't any because at high elo, veigar gets demolished by meta mid laners.
That said, if you want one thing to improve your play, your early game CS is pretty low. You are consistently hitting 25 CS at or after the 7-8 minute mark. This means that you are not able to buy a lost chapter at 5 minutes with a Doran Ring start. It looks like what you do is start mana crystal so you can hit the gold break down sooner. Try starting Doran Ring, and focusing extra hard on getting as many last hits as you can while only using Q's and auto attacks to kill minions. The extra AP from Doran should help a lot. And the extra health will help you survive lane from harass/ganks as well. If you are CSing adequately, you should hit 900 gold as you're running low on mana at around the 5 minute mark. As you get better at CSing, you can start moving points from Meditation in your passive tree into Merciless to adjust how much extra mana you will have.
You also run some odd runes. I'd recommend going with 3x AP quints and flat MR blues. This will help your CSing a ton. IMO, killing an extra 15 minions with the extra 10 AP in the early game means that you'll get your boots (and more than make up for the 3% move speed loss) on your first or second back.