GURPS

How much do you allow mages to pump up their missile spells when using the default GURPS magic-as-skills system? Particularly with casting level 15+ (enough to get a discount) and a few levels of Magery? The GURPS FAQ 4.3.3 here mentions that the total cost of the full charging time is discounted once - so at casting level 15 you can charge a 1 die fireball for 1 second for free, but you cannot cast a free 3 dice fireball by spending 3 seconds charging it - that would instead cost 2 energy points.

But what about the upper end? GURPS Basic Set page 240 says you can “invest one or more points of energy in the spell, to a maximum number of energy points equal to your Magery level”. Suppose a PC with Fireball-15 and Magery 2 spends 1 second creating a 2 dice fireball. This has cost them 1 energy point. Does this mean they could instead spent 1 second investing 2 energy points (their maximum Magery) into a 3 dice (discounted price) fireball? I saw this idea posted on the GURPS wiki here, but I haven’t found anything discussing this idea elsewhere.

Peter V. Dell'Orto has mentioned that even allowing the discount to apply to each charging turn hasn't wrecked his game, so I'm not worried about the balance component of 1-2 extra dice of damage; I'm just curious what other GMs would permit at their table.

I grabbed a copy of the 3rd ed Basic Set, but its a little intimidating haha.

Any recommendations for me to bring to a oneshot night to show why Gurps is neat?

For me at least, it's TL7. I just love that Space Race vibe.

Let's kick off some activity here with a question:

How much crunch do you, personally, like in your games?

Ultra Lite? Lite? Basic Set? Every book you can get your hands on?

Light on combat, heavy on skills? Vice-versa? Light overall with some aspects way more fleshed-out? Heavy overall with some aspects way more simplified? Are there specific mechanics you like to take full advantage of? Mechanics you like to gloss over?

No wrong answers, let's just get some discussion going