Rabbit pedigrees are a bit less... useful than horse pedigrees. They're all written by the owner and the vast majority of the rabbits are never registered (even so, they need to be at least 6 months old to be registered.) Because of this the pedigree is only as good as the honesty and record keeping skills of the breeder. Because they reproduce quickly most the big breeders pretty much have their own lines, and the smaller breeders and people starting out are a cross between a few. It's perfectly normal to ask "what lines is it out of?" when inquiring about a rabbit for sale.
Ask around and you should be able to find some information about silver lines. They're a quite rare breed though, which might make it harder to find answers. You should try joining some all breed groups if you want to research on FB too (such as
the unofficial ARBA group or the
topline discussion group, which has a lot of well known breeders.) Another place I like to look at to find breeders to ask about is from the results from nationals (link to silver results
here, though it is a bit behind)
Looking through that right now I can tell you a few breeders whose names I recognize: Chase Austin, Wade Burkhalter, Travis Finkle, Carrie Thompson, Jann Hall, Laurie Adams. I've bought rabbits from Wade Burkhalter, Jann Hall and Laurie Adams before and they were nice to deal with, but other breeds, not silvers.
Two things about silvers - in many lines they try to avoid crossing the different colors together. Personally I think that's a good practice. Also, in some lines florida whites were bred in for their body type and you sometimes get white sports popping up, that's also to be avoided.
There's big debate on the proper silver body type - traditionally they've always had a longer, sleeker type than all the other compact breeds, but because their standard explains the type the same as a florida white there is a push towards either breeding towards/into florida white type or trying to change the standard to reflect the type they have. Because that there's some inconsistencies with type you sometimes see between lines
.