Welcome!
If youre looking into contributing and having fun on an already well established server, Unchained is always looking for more help!
https://www.play-uo.com/
For anything in "Scripts" you should only need to restart your server. (Atleast with p57)
For "Server" files like items, maps, mobile etc.. you will need to recompile.
Well in your case what you could do is make meditation only rely on the skill
double skillVal = m.Skills[SkillName.Meditation].Value;
double chance = skillVal / 100;
if (chance > Utility.RandomDouble())
{
Which means, at 100 Meditation the person will have 100% chance of triggering...
Are they not the same..?
However, you might be able to use Centred# Global commands OR UOFiddler Map Copy which should be the way to go as its basically going to be the same XY
1 - Centred for sure. I think people also use DragonMap to make full maps.
2 - Most of your "Custom" files should be imported within C:\YOUR_SERVER\Scripts\Custom
3 - Look up "ExpansionInfo.cs" within your ServUO files
I personally do not use this for Unchained but after giving a quick look you could just add the main codes from the EventSink from the achievement (when looting) to
Daat99MasterLootersUtils
Right after the items are being sent to the backpack/or master lootbag