Nice pictures. I was thinking of one thing. Stridsvagn 74 was not introduced until 1958, but it was basically a Stridsvagn m/42 chassis with a new turret and a high velocity 75mm gun being mounted rather then scrapping them. It could work as the 1943 medium, being sort of Panther equal and not outside the realm of possibility for Sweden to produce in the time period. If Sweden really would have needed to produce a more heavily armed tank during ww2, that is probably pretty close to what would have been the result, since Landsverk was just upgrading the same concept over and over anyway. M/42 was an upgraded Lago (the Hungarian order) which was an upgraded M/40 which in turn was an upgraded L-60. So Stridsvagn 74 was the final tank in the Landsverk line. Then you could move all the mediums back one step and have a full medium tree. It was clearly seen as inferior to the Centurion tanks that Sweden bought canceling the KRV project, so it was not seen as modern at the time.
Alternatively you could use Stridsvagn 74 as the 1945 tank and KRV as a heavy. What I like about it is the direct lineage to the rest of the Landsverk tanks.