Eyes on health - newbie with a feral

[Wendy&Tiggy(GA)]

This is an challenging one.. the cat is feral and wont let her near his ears or paw pads (for now!). Should she just use diet to control the diabetes, or use insulin but can only use secondary monitoring tools to track?

Please see http://www.felinediabetes.com/FDMB/viewtopic.php?f=28&t=86983