The mast I am using is one I made up years ago for one of the first landyachts I ever built back in 1991. Thats my 10yr old son in the photo. He's now 30. The mast is two carbon fibre masts, one inside the other plus another short aluminum tube inside that, plus a short stainless steel tube over the outside of the base to stop the glass ones being crushed. It was basically the product of all the masts I had broken up to that point. The bottom half is very stiff as you can imagine, but the top is quite wippy. The only rule for masts in the mini class as I understand it is the mast has to be round in cross-section.
Haven't sailed it. We seem to be getting more rain than wind at the moment. Next day time low tides will be a week away so might strip it down this week and get some primer on those bare metal parts. It looks it's going to be a wet Autumn.