No worries with the maths, I'm an engineer and couldn't resist checking the weight with the right mulitplier, LOL!
I'm in the same situation with work, it has really been cutting into training time or leaving me too stuffed at the end of the day to do anything (excuses, I know, I should just suck it up and go to the gym) Even if I do make it for weights I still miss out on bike rides etc, but summer will make it easier.
Good stuff on the OHS. I've been doing them twice per week for the past month with 3x8 as a warmup for O-lifts. Last night I got to 60kg for 2 sets of 8, but only got 5 reps on the last set. I'll try again on the weekend. As DJ says on his website, they make you one piece, an animal! I love the looks of interest I'm starting to get from others in the gym as the weight gets more impressive, no one else does OHS.
I've got the same endurance grip problems, it affects my deadlifts. I'm pretty sure I've got enough leg and lower back strength to pull 160-170kg but couldn't get above 150kg at my last attempt at a max. I gotta do more farmer's walks!
I guess I have to set more goals as well to keep me motivated. I'm focusing more on the O-lifts at the moment, plus as I said I want to do some triathalons over summer, so going for max lifts won't compliment the training. In autumn I will probably set goals to improve in the big 3 lifts and work on that during the colder months. I've been stuck in the office for about 10 hours/day on average since July so i want to get out and about when it warms up!