Thanks for sharing your work. It's much appreciated. You asked...

Thanks for sharing your work. It's much appreciated. You asked for thoughts and I have some.
I presume you've used a current share price to establish the market cap for each company and then applied the SOL % ownership to establish NAV.
Nothing works perfectly here but I would be more inclined to apply the % ownership to the Equity represented in the most recent Balance Sheet of the Held company to determine a NAV for SOL.
For example BKW's equity number from their last published Balance Sheet (in September, 2021) displays $2,479,747.
That would offer about $1,066 to NAV rather than $1,501 in your chart.
They also have Cash on their Balance Sheet as well as some long term loans which should come into any valuation. It all gets quite messy no matter how you approach a valuation for a Company like this and your approach has more currency than my idea to lift numbers of an old Balance Sheet.
Just some thoughts.