The complete formula for experimentation is hidden, but the developers have given us a small clue. Namely the failure rate. Those funny red numbers you get when your skill is still fairly low or when you try to experiment too many points at the same time.
Calculating from the failure rate the formula for the success rate seems to be:
(50 + (Average_MA - 500)/40 + Experiment_Skill - 5*Points_Used) / 100
- is the MA of the resources weighted by relative quantity just like the experiment qualities.
is the expertimentation skill of your character
is how many points you spend at once. (If you try to spend points in multiple lines at once, you get penalized pretty badly and the formula changes a bit) With 75% chance, the red failure bar will show 25%. At 100% or above chance, the red bar is no longer visible.
If you have 55 in skill, you get 100% with MA 500. At 100 skill you have 145% with MA 500. This means you can only test out the formula at a fairly low skill while the red bar is still there.
Once you get 100% you can no longer get any failures, except criticals. But the system considers even marginally successful as a success. As you get higher above 100% the worst type of successes are gradually no longer possible. I believe that if your success rate is high enough, you can't get below great success either.
But there are two parts affecting the experiment result and the other one is the experiment roll. The roll is basically a random number which is added to your success rate to give the final result. But the roll has special cases. Like RPGs where a roll of 1 or 20 on d20 will always hit or miss regardless of your base chance. So if the roll is below a certain number, it will force a critical failure, if it's above another number, it will force an amazing success. This ensures you can get amazing with almost no skill and that you can always get a critical. Fortunately things which gives bonus to your rolls are applied before checking for the special cases. Which is why you then get less critical and more amazing results. High enough bonus might theoretically prevent any criticals at all.
This means that once you are above 100% (no red bar) you will only get failures from the roll and not from your skill. So things which affects the roll are more important to avoid failures. Like being in a research city or drinking Bespin Port. Both the success rate and the roll matters for getting more amazing successes, but for being able to use more points at once, probably only the skill matters. And there is a possibilty that there is a cap on your skill in this formula. But then you can't use the failure bar to test it out since your skill is too high to even get a red line. A force sensitive master crafter with +25 clothing would have a mean success rate without a cap.
The MA is the surprise factor. Having 100 in MA will be just like losing 10 skill points, while 900 in MA is a 10 point bonus. Unfortunately this MA is considered zero if none of the resources have MA effectively giving a -12.5 skill penalty. Which is not very nice towards Chefs and partially Doctors....
I strongly suspected Complexity to affect the chance, since it rises as you experiment. But it doesn't affect the chance at all. Also testing with various levels of crafting stations from public to 40+, there is no difference either. But both of them may affect the roll instead. The only way to find out would be to do tons of experiments with the same materials and use statistics. I remember an old post from someone who did this testing, but can't seem to find it again. Anyone with a link ?
And being in a research city doesn't affect the success formula either. But that is documented as affecting only the roll, so no surprise there. I have seen noticably better results from rolls in a research city than outside, but haven't done any tests on stations or complexity.
I never got into the holo grind and I avoid Dathomir if I can. So could any force sensitive crafter test if it affects your chance ? Novice Medic and Liquid Suspension would be an easy test, since there is no MA to consider. With Novice Medic only, the red failure bar will normally show 57%. (100 - (50 + -12.5 + 10 - 5) = 57.5 which is then truncated to 57) If the force affects it, then you should get lower than 57%.
Lunariel & Luno - Tempest