Test build "Maxed TT with late MW and low-levelled Venom"

I really think you should keep Shadow Star as level 1. Even level 1 saves you a lot of stars.

The reason why I see you would want to save stars is for either:
1. longer training
2. bossing

1. more stars for longer trainning
Pro: longer training means you get more time on a map to gain more exp.
Con: with all the points into shadow star at early level, you set back at putting points into other skills that would increase your DPS. A higher DPS means a higher killing spawn rate.
Example : If you made 10% an hour normally and you get to expand that time for half an hour, you make around 15% in 90 mins. That averages 0.1667%/min
vs.
If you make 12% an hour. That averages .2%/min

2. longer stars for bossing
Pros : You do save stars at bossing. Come out HT with extra stars.
Cons : Again, with all the points added into Shadow star, you could had increase your DPS and you could help kill HT a bit faster. Maybe not a whole lot, but in theory, it will kill HT faster. faster dead boss = less stars used. I remember reading that level 1 shadow star is already good enough for bossing.

Conclusion for Shadow stars at early level : It comes to what you like really. there is no set build. you can do what you want. it's just if you perfer to having just enough stars for trainning and bossing or adding points into shadow star.

-------

Regards about early venom, get TT as high as you can and as early as you can.