What is the most appropriate glucosamine/chondroitin supplement that you have used for bursitis?

None! Bursa have no cartilage . They could not work! I am dubious that they are of benefit in any form of arthritis!
Glucosamine. Hard to say as the bioavailability and standardization of dosage is not well regulated or established. While I use it in my practice it's efficacy is still open for discussion in arthritis, arguably helping maybe 40-50% of patients (comparable to placebo efficacy) it's efficacy in other conditions such as bursitis is even less well established.