Rheumatism, or the pain associated is caused by inflamation. So a strain high in CBD's will be the way to go. Also let plants ripen longer to full amber. More CBD and the THC degrades.
I have found MNS Med Man (White Rhino) very good for this application. Also Chemdog lines seams to be good at this.
Generally Indicas are better for this type of pain releif. OH, anything JC based likes subs Jacks Cleaner 2 or JTR even Pandora Box have a great CBD profile and work very well. Whilst delivering a little head to help make you forget or divert thoughts away from pain. DNA Kushberry was also very good.
Rheumatism pains are very similar to the pains I get from my degenerative disorder. If there is anything you need to know on this then let me know. My sister is a Neuro consultant, so with her knowledge and my botany knowledge, we have deduced some good strains for pain management - reduced apetites from pharma meds / pain.