How do I do that? Just remove the original ones and put these in?

BlackRainZ,

You could, but I wouldn't recommend it.
Instead, take any files you changed and put them into their own folders in the mod directory. (If you changed a file from the GameInfo, it should be in a GameInfo folder under the mod folder.)

Download a mod or two and have a look at their structure.
Mods go:

I'm not exactly sure. Gameplay.constants has these 3 lines:

OrbitBodyData
MinStarToPlanetGravityDistance 270000.0
MinInterPlanetGravityDistance 50000.0
MaxInterPlanetGravityDistance 100000.0

Which might be the size of the gravity wells, but on the other hand the outer ring isn't 2x the inner one. There's nothing in each planet type's entity files that defines their grav well size either. It might be hardcoded, but you can try messing with those values to see if it does anything.

Another thing you can do, however, if give every planet type a required bonus that modifies the grav well size. You might remember there are bonuses for +/- 33%. What you could do is make your own planet bonus, and then make it required for all planet types.

For example, PlanetBonusHighGravity gives +33% to grav well size:

floatBonus:GravityWellRadiusPerc 0.330000

You can make your own that gives it 100% (say, PlanetBonusDoubleGravity):

floatBonus:GravityWellRadiusPerc 1.000000

Then, you can make it required on all planet types. By default, you'll see this for each planet:

requiredPlanetBonusesCount 0

which you can change to:

requiredPlanetBonusesCount 1
bonus "PlanetBonusDoubleGravity" (using the same file name you created),

and every instance of that planet will always have that bonus.

Basically, yeah. You'd create a new PlanetBonus file (copy one of the existing grav well size modifiers and just change the value to whatever you want), and then make that a required bonus for each planet type. If you want, you can make a planet bonus for specific to each planet type (like, gas giants would have much larger grav wells than asteroids), and attach each unique bonus to the intended planet type

Looking as SOGE's files, it appears that these lines in the planet .entity file control the grav well and overall movement area size:

moveAreaRadius
hyperspaceExitRadius

Another question, are the jumpblockers hardcoded for their range? I wanted to make the range higher for jumpblockers

Yeah I was able to change that as well. I had another question. In game, I use the map editor to create a new map and the bars on the bottom which mention stuff like Orbit Radius, Phase lane length, Phase lane chance, Min distance, max distance. What do they all mean and which way is higher? Towards red or towards green?

Also how can I edit the map I am making to have only 1 or 2 players start in a given star system?

How about making it so only 1 or 2 players can start in one star?

Ah, I see. I didn't know that. Let me ask you one more thing then. When I make my own map, it takes forever to travel to another planet. I put the phase lane down and all of the other things down to the lowest and it still takes forever. For instance, right now I have a ship traveling from my planet to the star my planet is orbiting and it has already been traveling for 10 minutes and it is only halfway there. 20 minutes to travel to my own star? that seems extreme. When I play one of the default maps, it isn't like that at all.

I heard that if the entity files are in text code it loads faster, or is it the other way around?

I was about to answer questions here but now I see this is an epic gravedig. =|