Quick feedback on my one-pipe layout

Ahoy!

I have returned. Opened up some walls, and might have come to some tweaks to what I was originally thinking in my mission to re-add hydronic baseboard heating to my home. What was a simple loop system, which definitely suffered from some inconsistent heating, before I partially tore it out almost 3 years ago.

So it's 2 floors and 5 baseboards. 2 on the main floor, with the boiler, and the other 3 above, with the bedrooms. The original line ran from the boiler up to the master bedroom, which has about 12' of 3/4" baseboard, wall-to-wall. Directly below the master bedroom is the living room which also has 12' of 3/4" baseboard.

I would like to run TRVs in all the bedrooms. I was wondering if I could perhaps tie in the baseboard directly below, by installing diverter tees, as shown in the drawing. I read that when installing a TRV, I would need a bypass line that connects basically the main from before the TRV to the main after that zone. The existing baseboard had the main run along the top of the baseboard back to basically where the supply came in. I was thinking I could just put in tees before the TRV, and connect right back into the main return.



1) First, does this seem like it would work?
2) Would I have to use diverter tees or would regular tees suffice for As? (I ask because I read their might be distance requirements for installing 2x tees)
3) Would I need to install 1/2" in B? If regular Tees, I could do 3/4 or 1/2". TRV's would require 1/2" if I get 3/4" ones. Does it matter given the length is basically 3 inches?

The copper exits from that main baseboard and goes about 55' to the rear for the other two bedrooms, which each have 8' baseboards. Directly below them is the 5th baseboard, that is 12', due to a door taking the remaining wall. I'm wondering if I can do the same basically?



These have more traditional bypass lines, like as illustrated here: https://heatinghelp.com/systems-help-center/loop-system-hot-water-heating-q-and-a/

I'd basically be looping the supply after the 2nd baseboard around to catch the last diverter tee from the baseboard.


Can anyone see issues with this?

Thanks again in advance!