Multibit flip-flops (MBFFs) are widely used in modern circuit designs to save the power consumption. That is, the benefit of using MBFFs as opposed to single-bit flip-flops is sharing in-cell clock inverters among the master and slave latches in the internal flip-flops of MBFFs. Theoretically, the more flip-flops an MBFF has, the more power saving it can achieve. However, in practice, physically increasing the size of MBFF to accommodate many flip-flops imposes two new challenging problems in physical design: 1) nonflexible MBFF cell flipping for multiple D-to-Q signals and 2) unbalanced or wasted use of MBFF footprint space. In this work, we solve the two problems in a way to enhance routability and timing at the placement and routing stages. Precisely, for problem 1, we make the nonflexible MBFF cell flipping be fully flexible by generating MBFF layouts supporting diverse D-to-Q flow directions in the detailed placement to improve routability and for problem 2, we enhance the setup and clock-to-Q delay on timing critical flip-flops in MBFF through gate upsizing (i.e., transistor folding) by using the unused internal space in MBFF to improve timing slack at the post-routing stage. Through experiments with benchmark circuits, it is shown that our proposed design and technology co-optimization (DTCO) flow for designs with MBFFs is able to produce chip implementations with 20.5% fewer design rule violations and 47.7% reduced worst-timing slack with a little power fluctuation in comparison with that produced by the conventional design flow with MBFFs.