Because disc golf courses can be considerably different, due to the amount of trees, shule, etc. and because there is not enough $$ to go in and make courses exactly as you want them, it is very difficult to have "handicaps" in disc golf that would apply to more than one course
However, we have the PDGA player ratings, which I see that you have been learning about. Unfortunately, as a growing sport, every course does not have a SSA value, so players can not easily figure out how they are shooting, unless they become PDGA members and get a rating (which is one of their main benefits, so no way could they let players get these for free, because then most people would have less of a reason to join the PDGA in the first place)
The PDGA is working to standardize the sport with colored tees and pars that make sense for everybody, but with all the new courses and players, it will take time for it to catch on. As posted on another thread by myself:
The PDGA tee guidelines list the following, with my interpetations for better understanding:
Gold Tees - basically the toughest tees... the tees where a gold level player (1000 rated) also known as a scratch golfer (in golf terms) would be expected to shoot par - to shoot under on these tees is to play like a top pro - very few courses have true gold tees
Blue Tees - basically the advanced level tees or a 950 rated player... an advanced level player would be expected to shoot par on this course from these tees - to shoot under would be to play like an good advanced player or a weak pro, or if you shoot way under (very low scores), maybe a gold level player - on most courses on this site that have long and short tees, the long tees would likely fit here more times than not...
White tees - basically the intermediate level tees or a 900 rated player... an intermediate level player would be expected to shoot par on this course from these tees - most courses with short tees would likely fit here
Red tees - basically the novice/recreation/casual player level tees or 850 rated player - these players would be expected to shoot par on this course from these tees - these would likely be the beginner tees on courses already considered pitch and putt, meant to help newer players learn the sport without being too difficult
you can also go to the following link to check out the tees and how it is suggested that par be set for each type of hole with a specific player skill set in mind for each particular tee
http://www.pdga.com/files/documents/ParGuidelines.pdf