All of this depends on your firm. I've been prosecuting for a decade in a small firm, and for almost all of that, I've worked 9-6 or 8-6 with occasional nights to hit deadlines. I work longer hours when I travel. In big law, hours are long, and its hard to make the numbers work for prosecution, but more and more high end prosecution has been shifting to small firms, since the biggest companies see it as volume work (or classify high and low value IP). You don't need a PhD outside of chem/pharma, but you will need to know how to write a patent to transfer, and learning to write a patent is not trivial. There are ways to do it on your own, but its tough. I do deals for my clients, and tech transfer is a very different way of thinking than prep/pros. On the prosecution side, we work more as technical writers than lawyers, and we deal more with tech than law. If your only problem with tech trans is your hours, then the problem is with your firm and not your field, in my view.

I'm a big law patent prosecutor. We have probably the most predictable hours in big law. You generally know your deadlines at least three months in advance, and although rush filings do come up somewhat frequently, they are usually small, discrete projects that you can finish in a few days. However, hitting big law hours targets in prosecution is a slog. It's all highly technical work. Very little mindless paper pushing. So although our hours are more regular and we are not expected to bill significantly more than the minimum, it's still pretty difficult. You don't need a PhD, depending on your technical background. The biggest problem you would face in big law is your lack of experience and corresponding inefficiency. Prosecution budgets are really tight, but we have normal big law billing rates. If you can't get up to speed quickly, you won't survive. You will probably be asked to take a class year cut.