A/B testing is hard (on its own) for bottoms-up SaaS pricing just because you won’t have the volume you want to make quick, informed decisions. Always start with user research. Ask free customers for feedback on pricing pages over Zoom, have non-customers give feedback on checkout flows, etc. Narrow down your options before thoughtfully deploying A/B tests.

I'm primarily interested in bottoms-up SaaS, which relies on transparent pricing to function. But something people often miss is this: high quality product writing is the packaging. This applies to all parts of the product, but is especially important that your customers be able to understand what they are buying and how to buy it. Even companies with great traction are always leaving money on the table with unclear writing. Hire writers who have good design taste.

Re: cancellation policies et al. Not quite sure what your question refers to, but you should always be good to your customers. Give them the benefit of the doubt, be nice, treat them with respect, answer their emails, and let them cancel without calling someone on the phone.