Fractal Wingman frame just was too tempting for a HD build, but it is a tight build and hopefully others get some ideas from this post.
This posting has been waiting for several weeks to get the Wingman flying well enough.
I still need to get a 1S voltage booster for full effect, but 13 minute flights down to 3.1V (and 16 minutes if really milking it until the Walksnail/Avatar video dies) is already good enough, even without the booster.

I had some components in mind for the build and did quite a bit of "dry fitting".
First component was BetaFPV F4 1S 12A AIO ELRS Flight Controller V2.1. Being thin, with a plug instead of USB connector, having UFL connetor for external T shape antenna & 12A, seemed a decent choice for the HD VTX to still fit in the stack. When the FC was placed just right (see build images from both sides), the included UFL T antenna reached the front camera side-plates' triangular hole. I used some heat-shrink tube with glue to isolate the T antenna better from the carbon plates and to fit it snugly in the triangular hole (as you can see on the bild images).

Next was the choice between HDZero Lite and Walksnail/Avatar 1S kit.
Since Yves Fractal, Owner and Founder at Fractal Engineering, already has shared some info on his HDZero version (and also very recently announced Fractal Wingman HDZero BNF version in his shop), I decided to try the the Walksnail version in hopes that perhaps the 350mW would give it some range advantage.
I prefer HDZero in my whoops, but this quad is more of a cruiser, thus latency should be less of the concern vs better image possibilities.
However, at least without a voltage booster at 350mW Walksnail range starts gradually dropping aready from around 3.6V volts and at 200mW the degaradation starts at around 3.3V, so HDZero would definitely have an edge without a voltage booster. In my testing without a booster so far, Walksnail/Avatar 1S just essentially performs worse at 350mW than at 200mW in all usage cases. I will add a booster and will do more testing and may try HDZero Lite also in this build.

I used long M2 nylon bolts instead of the supplied metal ones and some M2 O-rings as spacers to get the VTX spacing just right. Supplied nylon M2 nuts were also helpful. I posted enough images to show what I did and how I had to rotate the FC & VTX for the best fit for these specific components.

I tend to flash my Whoop FC ESC's with BlueJay and automatically did so also for this build. The motors would not spin until I went down to 24kHz though. I set it all up with Betaflight 4.4 and it flew nicely enough, but felt sluggish on throttle management. I crash-landed 3 times (no damage) when cruising low to the ground because the throttle wold not pick up fast enough and perhaps gusts of wind helped too.

I saw Yves Fractal complaining about not being able to get BetaFlight tunes right for Wingman and his decision to go with QuickSilver Firmware. Coincidentally, over the weekend I had issue with my Fractal75 whoop build (https://rotorbuilds.com/build/31008) where Happymodel Diamond F4 AIO motors would not want to spin properly with BlueJay, until I went back to BLHeli_S.
So, this weekend I flashed the Wingman AIO ESC's also back to BLHeli_S and flashed QuickSilver latest FW for the FC. Should have tried one at a time to know what helped the most, but the throttle management was much better, I could cruise low to the ground even with wind gusts with very good throttle authority. I'll probably experiment some and will try again with BetaFlight as well.

Wingman does not like wind too much (have to fight against the wind and really picks up speed downwind) and seems to "slide" in turns (could be also my tune issue although I started with Fractal Engineering QS tune "Profile_WINGMAN_X12_ELRS_0.9.0_ICM20689_2022-09-06.yaml" from https://store.fractalengineering.net/ Downloads section).
I ended up hitting some tree branches by sliding into them and dropped the Wingman to the grass from about chest height. One of the arms got bent the wrong way and lost the tiny metal pole for fixing the arm in position. I had to cut a 4mmm piece from a 1.5mm drill bit as a replacement & it was a quick fix with some thin superglue (the hole for the metal bit luckily was not much damaged, but grab some spare arms if you can :) ).

So, a very tight, but cute build that can take some minor crashes and gives you long flights.

Matek VB2A5V 1S to 5V voltage booster probably cannot handle low enough input and is too big, so I ordered various Pololu Step-Up converters. My guess/hope is that 5V 2A Pololu 4941 Step-Up converter U3V16F5: https://www.pololu.com/product/4941 should be the most ideal option.

Voltage booster definitely needs to be over 1A capable for Walksnail 1S as Painless360 shows in his testing: