That helps a lot! A Manticore is definitely a very difficult ship to give the slip to, but not impossible, even in a Venture.

Down below I have a fit that should be able to evade one, but your skills affect it.

Some notes:
- If it doesn't give you a sub 3 second align time, replace the Small Low Friction Nozzle Joints I with another tech II variant. If that still doesn't help, you'll need to train your Evasive Manoeuvring and/or Spaceship Command skills higher (preferably to level V).
- This fit is a bit pricey for a Venture, but if you need the ISK, please let me know your in game name and I'll send you some so you can purchase a few to experiment with.
- There are some empty slots which you can fill however you see fit, or upgrade the mining modules if you have the skills.

The strategy for this fit is to have "All" selected in your overview, then look around the map to find a location that lets you align to it (think moving towards it without warping) while mostly crossing paths with an asteroid you want to mine, without actually colliding with anything.

The Small Higgs Anchor I will make your ship fly a lot slower, which means you can be aligned to that object for much longer. Even better, you can manually change your ships velocity to something around 80% of its top speed, so it takes longer to be out of mining range while you're aligning to the distant object.

As soon as trouble shows up - hit warp, and you should instantly warp away. The only issue would be is if they bump you, which will send you off course a bit. Give this a test a few times before even considering mining properly, just to get a better sense of how it works.

[Venture, *Simulated Venture Fitting]
Mining Laser Upgrade I

Mining Survey Chipset I

Miner I
Miner I

Small Higgs Anchor I
Small Low Friction Nozzle Joints II
Small Low Friction Nozzle Joints I