Guidelines for Points Total, etc. for my campaign

[scorpion]

I am setting up a streamlined GURPS campaign. Players will largely be my wife and teenage children. We have teenagers willing to spend family time, so goal is fun and engagement, NOT realism.

Setting:
Victorian England/Earth - year is 1870
Alternative Timeline - Steampunk Aesthetic/influence, causes revolutions to largely fail, i.e. more European courts exist, so lots of court-based intrigue - think Steampunk Swashbuckling, with a crew inspired by League of Extraordinary Gentlemen.

Play style:
Monster of the week - each adventure is self contained, because I'm not sure which kids we'll have
Substitutes ready - my nerdier kid may have friends join us
Play Style - Super simplified. For what it's worth, we're an observant Jewish family and generally play Shabbat afternoon, so no writing things down, computers, etc, so everyone's GCS sheet is printed, and everything is super simplified. If you are wealthy, you can pay for incidentals you need. If you are broke, you can't.

We have previously over the years done a Fantasy Game and a Steampunk Pirate game.

Each week: an NPC gathers the group, and dispatches them (via Airship) to whatever City on the planet they are needed. They then solve the Murder, Steal the Secret, Assassinate the target, whatever is needed.

I want the characters to be powerful, but still have room to grow.

Supplement's I'm leaning on heavily:
Steampunk (3E) and Steampunk 1 (4E) for background/NPCs
Monster Hunters - for paranormal/undead targets
Mysteries - for structure of missions

Supplement's I'm leading on less heavily:
Old West (3E) - for trips to the US
Magic/Thaumatology - For Alchemy ideas - largely for plot purposes
High Tech - equipment list
Swashbucklers - for fun story hooks, its the wrong time period
Social Engineer - I like this, players not so much, so it's more on background

TL: 5+1

Suggested point totals? I built up a character at 150, it was disappointing to build. The Monster Hunter templates suggest 400, which seems outrageously high. Is 200 or 250 more reasonable? Is 400? Is my anchoring to playing 3E w/ 100 points as teenager clouding my judgement?

I have been debating the use of tactical combat vs. simplified. Using Martial Arts+Gun Fu in Cinematic to make things more epic. I was generally planning to avoid the serious injuries. You hit 0, you pass out.

Any thoughts for how do I run this to:
Keep the game moving fast
Meaningful combat
Sense of accomplishment
Rapid character development