The reality is, no SS amp is going to recreate an 845. The imaging won't be the same. That being said, odds are your 845 is struggling a hair with bass performance on those Double Impacts.
Bass performance will improve. Imaging will suffer. Tonally, they will probably fall in about the same place as 845s tend to be a very linear tube and less rolled off than 300Bs.
My customer spent two weeks with the AVM A5.2 and the Canor AI 1.10. He thought the Canor was the best option with the exception that he is in a big room and the 20w in triode is not enough in his space. Reference listening had the volume at like 90%. I think he is going to move forward with the AVM 6.2 ME as he liked the 5.2 a lot and is just looking for a touch more refinement.
Looking only at SS, you are on the right path as those two will be very good. I am highly biased toward AVM, partially because I am a dealer but I do genuinely like the sound and build quality of their gear. I have had a 5.2 here for months and once you get through the break-in period, it is wonderful and the 6.2ME is quite a bit better.
I don't sell Pass but obviously it is excellent gear and highly recommended.
I would also suggest you check out the Canor AI 1.20, 50w into 4 ohms and it will do the job very well with those Tektons. I suggest this largely because I am the importer, but I am certain it will do the job well.
I know it still has tubes, but maintenance is MUCH lower and tube life is dramatically longer. The LTA Z40 integrated would also be a very good choice. I heard the power amp driving Tektons and it was a very good match.