Clear as mud!

I have tried holding the whistle sideways like a fife, and yes, it does help a bit though it is a bit more awkward for fingering.

I play in 2 local pubs in all seasons, autumn, spring, summer and winter, but the problem is year round (in winter there is often a fire and in any case the air temperature does not get too low, perhaps because there are often a lot of people). Indeed the problem is often getting too hot in summer!

I also have the same problem with excessive moisture with a Hohner Melodica, and the manufacturers have presumably anticipated this as (a) the mouthpiece is removable (b) There is a small metal button in a hole. which if you push it, air and hence (if you blow hard) moisture comes out the bottom. In extreme situations you can unscrew the keys which hold on the keyboard and remove moisture that way.

I think my problem is mainly spittle and not condensation (some people just produce more than others). Although I will check with the other tin whistle player I am nearly certain he uses the exact same brand and model. It is not just him who seems to produce a louder sound with the same type of whistle.

Perhaps in response to my earlier request, someone could make a few suggestions about tunes (on harmonica or whistle, either originally purely instrumental or vocal) which are reasonably easy to play but sound reasonably difficult, the whole point of this being to sound more proficient than you are!