We lead 1/3/5 meaning you start always the fifth is possible unless you have a connected face-cards. 98752 you lead the 2 not the 9. Vs NT You need at least a series with 3 cards. Last weak you led with QJxx against NT I assumed you had QJTx or QJ9x and took over with the ace and is cost us trick if you had led small I would have took the ace and play hearts towards your QJ and we will make 3 tricks. If you had QJ9x by overtaking we would also make 3 tricks because e we could finesse leaders 10. Vs Trump a series could be only 2 connected face-cards although a bare QJ is still very tricky.

Leads from a doubleton  Lavinthal with ginving partner a ruff  Suit preferences        

With a doubleton we will lead the first. But in 1/3/5 doubletons are hard to read.. If you lead a high card lets say a 9 it could be either from KJ9 9x or bare 9. Most of the time you can distinguish between the 9 being the third, but you could not see if its a doubleton or a singleton. Meaning you basically have no idea what to do with an Ace.. Take it and give you a ruff or hold it one time and than give you a ruff. If it was a doubleton, taking the ace could cost an important tempo, but if it was a singleton you should give a ruff direct. Conclusion dont lead doubletons in a game contract or higher, with a doubleton partner needs an entrée to give you a ruff and needs a stopper in trump to avoid all the trumps to be drawn out. So in a game or slam when partner leads a high card you could take it save with the ace and give you partner a ruff.

Against a part score its more likely we have the goodies to go for a ruff after a doubleton, so against a part score you should hold up the ace one time.

If you are sure to give a ruff to partner we could play Lavinthal. Meaning if I play the lowest card possible I would like you to return the lowest suit (except trump), if I play a High card I want the higest suit in return. Most likely I have an ace or so in that suit and could give you another ruff (if you have any left)

Suit preference signals are the best given the first time you have to discard a suit. Something new is a concept that you do not signal aces but queens or kings. Reason most of the tome you have no problem spotting what partners ace could be if he has one. But what happens if you have to switch a suit and you have Kxx an Kxx to choose from, its nice to know if partner has a queen to develop that suit Same with Qxx vs Kxx and all variants. Its nice to know other high cards instead of aces.

This does not mean you cannot signal an ace, sometime you have. For example if partner cashes his 4 tricks and have to switch to get it down.