I didn't try the speedster. Sorry I cannot provide feedback for it.
I started last year with the slingshot Hover Glide 24'' mast. My first board was the slingshot simulator 5'6'' with 30L. When you start foiling, a board with lot of volume will facilitate the waterstart and the touchdown.
But when 30noeuds shop received the AXIS freeride, I traded my hoverglide for it. It is much lighter than SS (8.2lbs compared to 11lbs). I also swap the board for the dwarcraft 4'6''.
I think the dwarcraft 4'6'' is still a good amount of volume while being not too big. I will not go with a very thin board (no float) until I can ride and tack efficiently.
As for the AXIS freeride, I was impressed on the first ride with it. Very stable, easy as the SS, and much lighter. I got the additional 24'' mast for shallow water. I am also expecting an XL wing soon (AXIS to release it shortly) which I will use in very light winds.
And what about the color brightness my combo has (not performance affecting but looks nice