HI guys,
I think there is a lot more to the Alu vs Carbon argument because, as with all things foiling, it is very complex. Peoples budget, riding style and genre all require different characteristics from a mast.
Aluminium and carbon masts both work just fine, they can both come in stiff or less stiff and heavy or light. The term "Glide" can be better described by lack of drag or efficiency through the water (performance). Some disciplines benefit from greater glide and more top speed, but others will make little difference.
The benefits of carbon are the shape can be infinitely varied in terms of thickness and chord length from plate to fuse. This also depends on the speeds you are normally foiling at. Thinner profiles are faster and more efficient. For low to moderate speed foiling alu or carbon will be perfect.
As aluminium masts are extrusions, their finish is usually a bit rougher than a carbon finish and the trailing edge will not be sharp (adds drag). The thinner profiles in both carbon and aluminium often have stiffness issues. Aluminium is harder to stiffen at thinner profiles without adding even more weight (thicker walls) and cost. The same goes for carbon. High modulus carbon is more expensive and cannot eliminate the mast flex without either adding more carbon, reducing the core thickness (adds weight) and expense. Some carbon masts can be quite light which generally means a foam core. The thickness of the carbon layup, profile thickness and the amount of foam determines stiffness. If you've ever lifted a high performance hi modulus coreless mast, you'll be surprised at how heavy the carbon mast actually is.
Some of the high performance masts now available have little to no core and mostly hi modulus carbon, but they aren't lightweight anymore, but are very thin and stiff. These masts are really only for racers looking for ultimate efficiency. They costs big time due to the amount of carbon, the labour to lay them up and the cost of the process itself (baking prepreg etc)
Back to the average wing foiler. If you are foiling below 25 knots speed, good quality carbon and aluminium will do quite nicely. You could even sharpen the aluminium mast trailing edges to improve efficiency (Don't do this!) as you will remove the anodizing and protective coatings leading to corrosion but you can make it a bit more efficient! Realistically, the average wing foiler will benefit from slightly better performance and lighter weight going with carbon, but at the expense of more cost and the need to protect and care for your mast more than an aluminium mast.
If cost is a factor, and you can rig 10m from the waters edge to your car boot, and ultimate efficiency isn't a high priority, the aluminium is great. Your average quality carbon mast will be lighter and a bit quicker. This is mostly appreciated when doing a long walk up the beach or to the beach.
Thinking even further the advantage of aluminium is it can be recycled easily and you can probably even make a few $$ on the scrap. Carbon, does not really recycle and will end up in landfill at some point

Having said all that, I would never give up my carbon mast, but I have also had some of my most memorable moments foiling on aluminium masts too.
Not sure if this answers all or in fact any questions, but FWIW ... Ride what makes you happy and caters to your chosen discipline.
DM