I use bartdunkeys youtube videos to build a reliable scoresender list. (just google "bartdunkeys"+"youtube") Because bartdunkeys has playthroughs of almost every game in neopets. And the playthroughs are quite skilled, that is, the timings are close to optimal (highest score in shortest time possible). It also gives u a good sample of possible scores when u watch the playthrough at different stages of play in the event u "end game" to send the scores that meet the 1000np reward.
Be careful of the youtube vids and timings though, some are sped up more than normal (1x) speed recorded playthrough, so their timings are not accurate.
Also, for bartdunkeys, NOT ALL the game recordings from stage 0, score 0. Only most. but not all. Make sure ur wait times start from score 0 til the score you want.
Also, be careful that not all games can be ended prematurely. Some games require that you lose all your lives first before ending. This isn't a problem at all usually but there are games out there that take time to lose/end even for low/med scores.
Tip: whenever u repeatedly use the same score list, make sure ur max score is not something too rounded like 900,15000,etc when the possible scores are like 14791 because after a long time, ur shell will hit the top score at least once and ur max score table, which can be viewed by anybody, will look extremely suspicious (having all ur max scores nicely rounded) to just about anybody who bothers to look.