Wargaming with lego and little kids

[J-H]

I'm most likely getting a set of Tidyboss 36x24 laminated battle mats for Christmas.
My sons are 4 & 6.
They have some of the knock-off Lego sets that come with guns and let you build tanks, WWI/WWII airplanes, etc.

I'm pretty sure we have enough minis and guns to throw out some blocks as cover and do some squad vs. squad wargaming with fairly simple rules. I have never played any tabletop wargame, with the exception of one WWII one, once, about two years ago.

What's a good game with rules online to look at to see how the simpler ones work?

My first pass at the rules is:
1) Each mini has two hit points. They sit down when they've taken one hit (easy to track).
2) Each weapon has different ranges (in squares), but they all do the same damage.
3) Movement range in a turn is roughly going to be equal to whatever pistol range is.
4) Players take two actions per turn, with different minis. Moving is an action. Shooting is an action. If we have a machine gun, it gets two shots.
5) Roll 1d6 for shooting. On a 4 or better, it hits. If the target is behind cover, a 6 is required to hit. Cover is directional and can be flanked.

I feel like there's a good chance that the optimal strategy may end up being "hide behind cover and shoot." That's realistic, but may not be much fun.

[Amechra]

BrikWars. You want BrikWars.

[J-H]

Yes, yes I do. Thanks!