eyes on health - newbie dosing

[Wendy&Tiggy(GA)]

Ruben had 1unit this morning and dropped to 48 at +3. Then went to the vets for an appointment. Vet says to keep on one unit unless drops less than 100 and then shoot 0.5. Needs dosing advice.

http://felinediabetes.com/FDMB/viewtopic.php?f=28&t=87741