Swapping the trigger pull weight spring in 527's is very simple and only takes a few minutes. Getting the factory spring out is the biggest trick because it's diameter is to large to be pulled out through the front, even with the adjuster screw removed, but it can be yanked out the back with a little effort. I have a set of picks similar to this
https://www.grainger.com/product/2M...VMgGtBh0dkg6oEAQYASABEgLSSvD_BwE&gclsrc=aw.ds and it made quick work of getting the old spring out. I bought a handful of trigger springs from James Calhoon a few years ago and replaced all of the trigger springs in every 527 I've ever had. If I recall James only charged something like two bucks per spring for them so it's a very inexpensive mod. and the spring from James is smaller in diameter so it'll go in through the threaded hole with the adjuster removed. With the spring from James you can adjust the trigger down about as low as you'd want. As I mentioned earlier I had one of mine around 8oz for awhile but prefer them in the 12-14oz range best and that's not using the single set feature. For me pushing the trigger forward to set it puts it in an odd location for me so I don't use it.
Timney doesn't list a trigger specifically for the 527's so are you guys with Timney's in your 527's using the one they have listed for the CZ 550?
As has been mentioned the factory 527 trigger is actually a pretty decent piece and with just a simple spring swap can make it tunable to about any pull rate you want. I'm all for using aftermarket triggers but with the CZ's I'm just not sure there is anything to be gained by swapping out only part of the trigger assembly that cost $160 versus a few dollars for a spring swap.