I repotted a potbound jasmine 6-8 weeks ago into what ive now realised was a pot that was too large (more than 1 or 2 inches larger than previous pot). It looks ok but no buds on it at all, and the soil quality was not as great as Id hoped, so I plan to repot it again. What size pot should i choose now?
To reiterate was @Tim Nevins commented - plants do not have a tape measure. For some plants, Ficus carica being a classic example, restricting the rooting environment does encourage fruiting. Effectively, presented with a large volume of good growing medium plants may take advantage of the situation and put on significant amounts of vegetative growth. However, they will in time use what they need and balance will be restored. Just a little patience required.
This, I doubt is the case here - you mention the soil quality is not great, so it is unlikely to result in rapid vegetative growth (you do not mention if other growth has been affected). Whenever repotting or transplanting a plant there is inevitably some degree of transplant shock, which will set back growth and flowering. Careful watering and a little time will likely resolve the problem. Most plants commonly referred to as Jasmine - Jasminum (true Jasmines) and Trachelospermum (star Jasmines) are vigourous growers, it may be that a little feeding is required if the soil is poor.
Mature plants do not generally require repotting more than once per growing season. I would avoid repotting again soon, as this likely to stress the plant more, and with a bit of TLC your plant should start flowering again when it is ready. Be patient.