were can i find the thc % for all the strains trying to make an informed decision short of googling them all individually is there a site with them listed?
Not to my knowledge. There *are* individually held databases containing testing data (for example all strains tested by a given lab), but so far as I know, these are privately held.
You can google individual strains, and some of them will come up with THC measurements, but that information isn't going to be nearly as useful as you think.
For obvious reasons, you shouldn't accept published numbers from the seed sellers without a huge grain of salt.
Even assuming the published numbers actually represent real testing results (which you don't know for sure), if you were to simply pull randomly published measurements from the internet (or wherever), unless those measurements are done side by side in the same lab using the same technique, you can't really compare them fairly. Since THC testing is not standardized, there can be differences in measured THC content depending on which lab is doing the testing and how.
Next, published measurements should generally be considered the CEILING of THC potency of any given strain. That's because the tester is going to take the very best top bud from their very best phenotype plant, hand grown under ideal circumstances and picked at its absolute peak, carefully hand manicure it, and test only that. Even the rest of that SAME PLANT may not have quite as high THC levels as the tested sample.
YOUR grow of YOUR plant in YOUR growroom may not (and statistically speaking, probably WILL not) represent the absolutely most potent possible bud from any given plant.
Even simple phenotype selection matters a lot. I don't think any of TGA's strains are actually inbred lines, and that means you can expect some degree of variation in plants grown from seeds from the same pack.
If you say germinate 10 seeds from a pack, its entirely possible you'll only get 4 good females (or less!). Selecting from only four plants, there is a pretty good chance that NONE of them will be the best possible representation of the strain in question. That's why people looking for the "best" strains will often start with 2,3,4 packs of seeds to do their selection to find that "killer" plant to use as a mother for further cloning/propagation.
From this perspective, buying a high-quality clone from a known excellent phenotype (if you can) makes sense for a lot of reasons. Even if the clone costs 1/2 as much as a pack of seeds, you're way ahead of the game if its a great phenotype.
Yield matters too. Which would you rather have. . .a plant that puts out 1 ounce of 24% THC bud, or one that puts out 2 ounces of 18-20% THC bud?
I'd make the argument pretty strongly that a few percent difference in THC is, for practical purposes, meaningless.
Does it really make a difference if it takes 2.4 puffs to knock you on your ass vs 2 puffs? Any of these super-strong strains are PLENTY strong, even for seasoned smokers, and I'd say you should concentrate your selection based on other important factors, including flavor, yield, necessary length of grow, and difficulty of growing.