i can tell you what i would do in this situation tomorrow morning. no matter what the number, as long as it is a ways over 150, i'd start thinking about either not shooting anything and letting some of this 8 unit buildup clear out of his body or if i considered shooting, i'd shoot 1 unit and that's it. no more.
then i'd pick up some ketostix while i was out tomorrow and test him for ketones tomorrow night and continue on that path for several days, as long as the numbers warrant it.
and in a few days i'd give a good look see to the numbers i get over those days and see what i think. i'd even put a yell out here for "can someone look at my post-hypo numbers and help advise?"
yes, testing a cat in the beginning is a pain in the ass to put it quite frank.

i used to have to chase Mousie in circles around my house for no less than 30 minutes, often 45, until she was so worn out she couldn't go any further. that allowed me to get my hands on her at least and then i recruited my fiance to help hang on to her for the actual testing and pilling that she was getting for the first month. she was a street rescue that i had never touched prior to her diagnosis so you can just picture that ordeal.
put simply, their lives depend on us doing what you are doing tonight. if we don't do it, they get sick or they die. in time, they learn that what you are doing makes them feel better and they just live with it. I pop the top on the vial of test strips now and Mousie is running AT me, bright eyed and bushy tailed and voluntarily sits for her tests.