I purchased a Solarmeter 6.5R and wow! My bearded dragon enclosure is only reading 0.5 and my tortoise enclosure is 1.6. Fortunately, they both get ample time outside in natural sunlight. I just ordered two new Arcadia 12% bulbs.Which one? 12%?
Understand that anything we tell you is a guess. There are variances in bulb construction and performance and also how they are used in each individual enclosure.
Having a Solarmeter 6.5 is an indispensable tool for measuring bulb UV output and getting the mounting distance correct.
https://www.solarmeter.com/model65.html