Hi Catherine,
I, too, help mothers with some bottle feeding if baby is not at the breast
for whatever reason.  We have had good exprience using the A style nipple
when a mother is mixing breastfeeding with some bottle feeding or is not
breastfeeding for a temporary period of time.  It has an elongated round end
with a wide base.  I have not had good experience using the "orthodontic" or
shaped style nipple.  And I freely suggest that mom not use the "flat top"
style.  At any rate, the A brand (slow flow type) has worked well for us at
our center.  Since it is fairly difficult to find in our community, I keep a
supply back in the store room and use as needed. If you are not familiar with
this one and are interested, let me know.  I will be happy to share whatever
information is desired.
Pardee Hinson, MPH, IBCLC