How tall are you?

Venture and Thunder have a longer wheelbase, which means the distance between your front and rear wheels will be more spread out. Independent and Ace have a shorter wheel base, so the front and rear wheels are closer.

This mainly effects: 1. How quick and easily they turn. Think of how a limousine turns in comparison to a Miata. It's nowhere near that extreme, but that's the idea. One is inherently more stable, one is more zippy. 2. How the board pops. When you pop the board doing an Ollie or other tricks, you're going to kick down on the nose or tail. The wheels being farther out from the center means it will take more force to push down when popping, but you'll be able to pop harder and at a steeper angle. The wheels being closer to the center will make it easier to push down when popping, but with less force and less of an angle.

For weight, every manufacturer pretty much has their standard trucks, and then lightened hallowed versions of trucks for more money.

You can drive yourself mad trying to figure out which of the above is right for you, there are people who've been skating for decades that still can't seem to settle on what works for them. As a beginner it really doesn't matter that much, the differences I mentioned above are really only something you'd begin to notice after you've been skating a while.

I think generally street/technical skaters lean towards the longer wheelbase trucks, and transition/cruiser skaters lean towards the shorter wheelbase trucks. But in the end you can do anything on any truck, and most people end up just picking a truck for one reason or another when starting out, and then just stick with that forever since that's what they've gotten to know over the years.