Checking records shows these models in use:
#3 has two ea Monitor Injectors
#6 has one ea Ohio #7 and One Monitor #7
#10 has one ea Monitor #7 and one ea Freidman #7
#12 has two ea Monitor #7
#15 has two ea monitor #7
#16 Has one ea Monitor #7 and one Freidman #7
#17 has one ea Monitor #7 and one Freidman #7
#20 has two ea Monitor #7
#22 has two ea Edna #7
#25 has one ea Monitor #7 and one ea Monitor #8
#40 has two ea Monitor #7
#41 has two ea Monitor #7
#42 has one ea Ohio #7 and one ea Simplex #7
Don't have much on the RGS early days but at least RGS 5 & 13 did have Nathan nonlifting injectors for the fireman added by the 1905-08 time period but 10 years later they had been setaside for spare parts (canalbalizing).