I have a database in which there are patients. Sample size is 1000. (100% response due to spare sample/replacement etc)
20 GPs were involved. Out of 50 GPs, 20 were selected and 50 patients were selected randomly by each.

To use survey modul and to calculate weights, shall I use this one (svyset eaxmple):

One-stage clustered design with stratification
svyset su1 [pweight=pw], strata(strata)

where pw=N/n (total number(50GP) of patients in given strata (agegroup/gender) divided by the ones in the sample.
Strata should be the GP id code?
And su1?

Or is a different formula should be used?