I've discovered a tip watching Phantomas input ("up" in straight lines, not shown in demo) which helps a lot for downhill.
With save state to learn best trajectory (thanks Mame) I've smashed down my 13 years p.best of 35"78 with more than 2.5 seconds ! (33'25)
I'm still worst in speed (11"413 vs 11"050) and jumping (152m vs 155m).
Stable in short track (old:43"73 new:43"66) bobsleigh (around 41"50, but only if I manage a perfect start, that's the bad event of the game, needs too much luck with the start, that's why it's very hard to finish a game with Mame settings) and cross country (around 5:00min, best 4'58"12, but even with that, I get lower score than all other events where I can get around 1400 pts ; I must miss something, but what ??? if someone know, thanks to tell)
Concerning the characters, for the moment I've tested those from JAP(joe kudou) RUS(Alexei Rigel) GER(Karl Vain).
JAP is complete, RUS is very good on some events (bosleigh) but sucks too much on slalom, so it's hard to finish the game with him : I only managed once with 28"96 on slalom
for final score of 10782.
GER sucks a little on jumping, but is very good on downhill, an affair in term of points : it was one of my 2 favourites in Decathlete (with the GBR) and he looks fine here too.
I'm building a page with all my best scores (snap+inp), I will give the link here when finished.
And hope someone else will compete on this