MvM General Engi Tips?

What I do for Engi:
1) Upgrade metal capacity twice.
2) Then upgrade wrench attack speed and sentry firing speed.
3) This is usually where the tanks start coming in so I whip out that wrangler.
4) Next upgrade my widowmaker's penetration and attack speed.
5) Upgrade sentry health.
6) This is usually the last wave, so I go with speed or blast resistance.
If a sentry buster comes for me, I usually run towards it with my sentry in hand, set it off, and run away (normal speed should just be enough). I also grab 3 instant upgrade canteens near the last waves.

Anyone have tips to improve on this? If so, pwease leave them below. <3

Argh keep it all in one thread! lol.

But as far as I can tell, those tips seem legit. The only thing you need to worry about is sentry placement and looking up a few youtube videos is simple enough to figure that out.