I used the AmeriSource syetem for a bit, and you can control what is ordered by placing the order yourself.
Sign up for eFax, which is a free service to receive faxes via email (you have to pay to send faxes), and have your techs fax you the order on Sunday. That way you can restrict access to the online ordering.
I'm sure your techs would rather send the order to you instead of actually placing the order, so compliance should be good.
I used to do basically a mini-inventory every Wednesday. We had a 230 bed hospital so we were around the same size. It was a horrible, painstaking ordeal, so no one bugged me that day, but I managed to place the big order of the week in the middle of the week, then just use the Want Book for the rest of the week. We also tried the handheld with varying degrees of compliance. It really depended on the mood of the staff. I'd do a quickie check on Friday, just to make sure there were no suprises for the weekend, and I'd do a remote order on Sunday.
It worked for me. I ran about 12 turns annually (not really that great, we had Pyxis), and my contact compliance hovered around 80%, which pleased the bean-counters.
Basically, you've got to establish 'Your' system, make everyone aware of it, and stick to it. Once you're got a system carved in stone, it centers you for the rest of your responsibilities.
I found that having PAR levels makes Sundays orders easy - very seldom do I come into ordering problems on Mondays. The PAR levels and order #'s are there so there is no guessing on quantities. We also utilize a want book so if a patient is using a lot of a certain med it is noted on the want sheet so extra can be ordered.