Moving the carb-up period to where it works for you would seem OK to me ... I mean, 2 days and 6 or so hours of carb-up is the same no matter if it's a weekend or not ... there's nothing magincal about the weekends ... that's just when I prefer NOT to train.

As for shortening the duration of frequency of the carb-up ... that's kinda altering the basis of the program and you would be playing guinea pig at that point. Maybe it will work for you, who knows?