Have to say I have just continued to play with the original solo method and it's not made things significantly harder (more frustrating yes but not harder!)
I nearly won my last game in 1982 until I scanned Europa and realised it had a thin crust with an ocean and put another 16 points on the table with not enough time to complete any more missions! If only it had said advanced probe!!!!
My issue with that scoring, is that it doesn't necessarily make you go for the outer planets missions, sure, probably most of the times you'll need to make some missions, but you can just go for big score on the base game, and leave the outer planets quite un-explored.
How do you deal with the explorable missions, you only count the ones you reveal, or another method?