All masts of the same size should have very similar flex/curve attributes, therfore a Gun mast should set as well as a neil pryde, gaastra etc. The difference you get with masts is the strength, weight and people being tarts who only want neil pryde etc. Best bet is to see where the masts are made. Most are made in the same 1 or 2 factories.

Comrade Crash
I beg to differ re
['All masts of the same size should have very similar flex/curve attributes']

While they maay have the same flex rating many seam to flex in differnt places.
Maybe this is not much of an issue for lighter guys but for the heavier guys it certainly makes a big difference.
Trial and error is the best method
That said, the site Comrade Nebbs has pointed to certainly looks the goods.

Stehsegler,

The IMCS is the stiffness. Once again this has nothing to do with the bend characteristics.

The stiffer the mast, the more force you need to downhaul, but this doesn't say where the force is distributed. It can be argued that the flex characteristic is more important than the stiffness, but since mast manufacturers only really publish their IMCS it's difficult to compare. You can have two masts with the same IMCS number, and totally different flex curves, and the one sail will set totally differently on the two masts.

Please check the link I posted above for more information. It certainly opened my eyes

Kremlin and neb are right. Response rate and material distribution all have big effects on masts even though they might be the same stiffness (IMCS). There is also a bit of freedom in mast curve, i dont know about all the pryde masts but some where on the flex tip side of constant curves.

Pryde sails do tend to be very mast specific, but maybe windsurfingsales can help you out a bit by getting their hands on some prydes and rigging them on gun masts to advise on how well they set.

Thanks guys...I will try to find a gun mast in Melbourne to rig the expression. It may look good on the grass, but its how it feels on the water that matters...and no doubt what feels good to me will feel different for someone else!

It would be great if ALL manufacturers used one size mast of the same bend characteristics for their entire smaller size range...dream on!

Comrade Crash

Did not mean to come across heavy handed or attempting to shoot you down for your thoughts and views... all valid.
i just think with most things windsurfing based, it comes back to horses for courses
This is particularly relevant when you start factoring in different sizes and weights of different sailors and how that effects their rig.
I have to agree in part with Comrade Stehsgler about the flex rating of masts... in fact this is one of the main reasons I have shied away from the skinny as it tends to 'over react' with aa heavy sailor (85 kg and above) by this I mean it tends to feel very soft as it is constanly flexing.
I use a 100% carbon wave mast (rdm but not skinny) which works a treat. If I rig the same sail with the same manufactuers skinny mast i find the sail soft and twitchy. On the other hand a comrade of mine who is around the 75 kg mark lurves the skinny on the same sail
?
That said 2 suposedly identically rated masts by 2 different manufacturers will perform quite differently on the same sail in my experience

Horses for courses as i said and if possible it's always worth while trying before you buy (easier said than done though)

And just for the record i have been runnning a 100% carbon 430 North viper with the 04/05/06 Pryde Expression and Pryde Search and it works an absolute treat !