Yes, I'm very familiar with your efforts. I pondered a screw press; but, I agree with you, it's too slow and provides more mechanical advantage than needed. Your latest lever press seems to be an elegant solution based on your design requirements. Since I go to the range with a veritable baggage train, a compact size wasn't one of my requirements. That doesn't mean I wasn't thinking about your efforts: Had I dovetailed the column to the base, instead if screwing from below, then my unit could be knocked down. But, since I'm not a proficient dovetailer, I passed on that idea.