Nice video
As you can see on what I'm doing building the KV-122 I am getting as close to the JS-122 as you can with out buying the Tamiya kit for $1000.00 bucks.
Now that the JS-2 kit is out you can buy some of the spruce for it from Tamiya USA like the turret its a 1s turret but looks better then the Juckenburg KV-85 conversion kit and is more to scale .
The barrel price is ok but just to get the Mussel brake be ready to spend a lot of dollars even for any other spruce but all in all if you convert a HL KV-1 and even use the Profiline KV-85 turret kit or the Tamiya JS-2 turret it still cost less then buying the whole JS-2 kit .

Thanks
Jimmy