I have just got a Hotsails 5.8 fire (2010?) and don't have a suitable mast, and don't really want to buy a flex top mast just for 1 old sail, (even though it's only been used a couple of times) although i have a 4.0 Kauli, for a couple of KS3s, it needs a 4.3, and a fairly long extension. It rigs awfully on my hookipa 4.3.
I have an ezzy hookipa that is damaged inside the top end of the bottom piece, and the tip of the top split (now repaired) but the ferrule is good, and fits well inside the base of the Kauli.
I'm thinking of cutting the ezzy to 30 cm plus ferrule to use as a base extension for the Kauli, to get a flex top.
Good or bad idea? and is my chinook extension likely to fit inside the new base? Thanks for any input, and has anyone tried similar?

jontyh: Yes, good idea chopping a bottom end. This is how I tune my Naish Force 5's, which I appear to be slightly flex top. But, you would think that the Ezzy 430 mast would be in the ball park of the HSM sail ?

PS/ I dialed in an Ezzy 5.5 Cheetah this way too.

Well, you know. Belly and twist off... belly and twist off 👍

As PS said, you have to chop them too. Below is for my 4-8cm ext sails. Below that is the 30cm RDM extender.

In cases where you don't need much a mast tip extension is great too. Can't find my photo but it's somewhere surely.