data modeling - Dimensional modelling few questions -

i getting familiar dimensional model, started looking @ health claims process. trying acheive following:

1) ability report claims patient speciality , service provider (monthly, quarterly , yearly)

2) claims referring provider service provider

3) claims monthly payments received (1) , (2)

4) claims month of services (1) , (2)

here dimsion model:

factclaims

charge amount

payment amount

service date key (fk)

payment date key (fk)

patient key (fk)

service provider key (fk)

facility key (fk)

referred provider key (fk)

dimension tables:

dimserviceprovider serviceproviderid (sk)

service provider name

speciality

dimpatient patientid (sk)

name

address

dimdate

dimfacility facilityid (sk, pk)

facilityname

facilityregion

facilitystate

questions: 1) should separate fact tables charges , payments?

2) not sure whether thinking correct referred provider key (which points dimserviceprovider)

3) rule of thumb combine of dimension tables or separate them? rules combine dimension tables or keep them separate?

whether separate payments , charges depends on kind of reports going run. also, did consider payments/charges insurance, secondary insurance, if applicable, , patient/person responsible patient?

if keep referred provider key, should provide special value self-reffed patients.

there no dimensions in model might considered consolidation.