Well being the generally impatient type, I decided to go ahead and use one of my spare 11sp DA chains and swapped out the 11-34  to the 11-42.  Figure if it doesn't work I haven't messed up my chain since I won't have cut very much off so can still use it later on 11-34 setups still.

There's a setting "rd protection" or something like that in the dreds app that allows you to toggle it on or off. If you've only used the factory app, it should be on by default.
I don't repin chains-just use another quick link. Its not a problem. There's stories of a guy who built an entire chain of quick links and rode it for a few hundred miles. I have over 2k on a chain with two, but my max sprint is only 700w or so.

I will say, one complaint I still have is the shorter chain requirement of the WT setups in general (due to smaller derailleur cogs based on comment earlier in the thread) - you basically "ruin" a chain because you've shortened it past what most other group/brand setups would need.  So my advice to anyone "on the fence" would be to start with a lower cost chain, that way if you decide you don't like it and move to something else, you won't have effed up your DA chain .  For my swap to the 11sp gravel, I put a couple links back in it since moving from 11-30 to 11-34 cassette, and didn't want to cut another chain lol.  I know that's not the norm anymore, but before quick links we all used to re-pin chains, so it will do for testing, anyway.

No, you can't block the large large, and the bigger pulley wheels might give you fits with a 34. The 30 will be fine. I can't use the big/big with a 34 on a TX with an ospw and chain length set that allows use of 3 smallest cogs on little ring due to jockey wheel interference. I can set b tension so that it doesn't lock up but it still grinds and the mid cassette shifting goes to hell with high b tension. I'm going to go back to longer chain and block the smaller cogs, which you can do.

Which caliper you use? There are 3 wheeltop models..thanks