WS drops from end game bosses

This idea comes a bit from the official server but perhaps we could have something like this adapted to ML.
Bossing every day is good in Maple because you get a gem that is worth Mesos on a specific NPC, the Mesos gained depends on the boss's difficulty and is divided by how many people participated on the boss. The most important thing is the reward points you get by killing most bosses (all of the bosses that grant these points are entry limited, so bosses like Zakum and HT, map bosses are out), with these points you can purchase goodies on a special tab in the cash shop, all of them are character enhancement items (cubes, protection scrolls that are pretty much ws and so on).

So to translate this system we could add some sort of currency to bosses that allow bossers to purchase goods from an NPC, she could look like this:

We could purchase stuff like WS, CS, Pink and Purple Capes, Clean Slate scrolls. Perhaps even goodies to make bossing easier like Gelt Chocolate or Swiss Cheese... Who knows perhaps even add this little pot to the game:

All that will be down to the GM's tho. I also considered if making all these goods except capes untradeable to avoid a bit of the mules.
The bosses amount of currency could be shared like in Maple (everyone that participated gets the same reward) kinda like the Xmas presents, but we need to do something so is not exploitable with mules, that would be an issue because I don't think to make it an actual drop would be good since everyone would just roll for it and make gains RNG.
The amount of currency would depend on the boss's difficulty, bosses like Papulatus or Ravana would give a small amount but bosses like Pink Bean or HT would give more, being Bean the boss that gives the most.
The mules and such could be an issue so I would like to hear ideas to deal with them, on the official server muling isn't as big as it is here since you get the most rewards from having all your characters on the same account, on top of that the hardest bosses have big lv requirements to even enter and when you go inside they have so many attacks that can 1 shot you that an afk char wouldn't last long on harder bosses.
If we can find a way to deal with that I bet we can make this special store work.
About the gems boss already drop certain items that are worth Mesos, perhaps make em worth more or add a drop to bosses that don't have a Meso drop. If we really want to make it like the official server then make 1 etc 100% drop which value is Mesos/number of signs but well that's up to debate too, I'm just happy with a drop that is worth perhaps 1M or something, 500k on lower lv bosses

 

I think idea of making exchanged items untradable is a nice touch, but can easily bypass through selling services as we already seen with 65% scrolls, White Scrolls.

 

I am aware of these flaws, but they are so hard to fix. There is also the option of making an actual drop, stacks of special coins that people can pick up, so the least people that go to the boss the more stacks of coins are available for attackers but it kinda impossible on Pink Bean where up to 30 go to kill this boss at the time, I also I kinda dislike the reward is bigger the least people you have, I want to make bossing good not only for the top tier players if you HT with 6 men you should get the same as 12 ppl at least coinwise.
I really want a store like this to work cos this would incentivize bossing, imagine high lvs going to papulatus or zakum cos is good for them, or hey go to a zakum with lower levels and get something out and have fun doing so.