No, there aren't any "certain vehicles for certain jumps", but some vehicles are just too slow.

Try jumping at slightly different angles. One time I had to jump like 20 times off the same ramp to get it right. Sometimes you just fly too far. Every unique jump has an exact landing spot.

quote tawncomps

m really havin a hard time pullin that blueberry acres jump. the first one. i always hit the oposite barn house and even if i do landed safely,still it's not a unique for me

I did it with a Police Rancher, ...right after I destroyed at least 5 of them in failures / crashes.

quote tawncomps

if only we had a checklist on the game menu itself cause sometimes, we didnt noticed that we already jumped that one but we keep on jumping on it again. is there a new way we'll be able to know that we already jumped that ramped already? so that there'll be no more double jumps to no avail.

1. Go to http://myepsilon.org/content/maps.htm and download the "Unique jumps map";
2. Use "Microsoft Paint" to cross out the ones you've done, but make sure, that you never cross out anything before you save the game.

If you're going to use the "Paint" program to cross out those jumps that you've already done, then you need to be careful not to cross out the ones, that you did since the last time you saved the game, or otherwise there will be a danger that you might forget about something at some point and eventually every jump will be crossed out and you'll be 2 jumps short of 50 and you wont be able to determine, which ones you've done, because you wont remember.

I learned that lesson with the oysters the hard way.