Unifoil alu mast pros/cons

Looking to buy a 2nd mast. Please link me to earlier topics if any.
60kg rider in poor Baltic sea conditions. Mostly prone but also wing incl. DW. Always on 75cm
I expect that the benefit is price so my doubt is the connections. I know that it will never be as a single piece carbon mast, but
I had earlier owned a couple of alu-mast from two different brands, and the fit was all but good. I guess that the mast-foot can be glued to compensate, but any feed-back for the fuse-mast connection. Is Uni any better than other brands? I feel like the conic design works very good with the carbon mast.
Other question. Heard from riders with carbon mast and alu-fuse that the fit gets looser with time. Should I expect the same when the female is carbon.
Last I was thinking about getting 85cm. If I want to cut 5cm off after some time, will the threads be long enough or will that also need rework.
Thanks in advance and stay foil-brained
PS: 2nd mast is to avoid the extra work of mounting/unmounting my DIY finger-blaster