I just wanted to provide some lessons learned and a few comparisons on the SB foil platform. Hopefully this will help provide insight when you have questions on setup or purchasing. As an engineer, I prefer understanding the physics to figure out what will work and won't work. I don't know it all, and I'm open to anyone's thoughts and insights. As a beginner foiler, I tried to understand what would be best for learning with and progressing into.
Setup: Starboard Foil 147 board and Ezzy sails that range from 5.0 to 8.0.
Foils: GT (800cm wing, 33cm stab, 75cm Fuse, 85cm Mast); additionally the 115cm fuse & 220 Stab (1100cm wing on order).
So, essentially, I have most of the configurations available.
Translating foil parts into physics:
Mast: The shorter masts are more comfortable for beginners as they don't get very high. This also helps when they're putting them on non-foil board that have a flatter nose so you won't go over the 'handlebars', or pitch-pull. If you marry the longer masts with foil specific boards, the designs are there to keep you from pitching over (like the Foil 147). With the shorter foil masts, you don't have a lot of room for margins, meaning there isn't much room for the sweet spot to foil, so you have to very good at judging altitude when learning. The longer masts provide more foiling altitude range, which is nice to learn with as you pitch up and down to figure out the right balance. When in very flat water, all of these masts work, the taller masts are needed in heavier chop. I was on a freshwater lake last weekend with 2-3 foot waves, and my GT foil wasn't quite tall enough for a smooth flight between the troughs of the waves.
Fuselage: The length of the fuselage plays in the reaction of handling. Imagine a buss vs. a small car in a slalom course, but with pitch (up and down control). The shorter the fuse, the faster reaction time for lift and descent. The longer, the slower. My experience between the two fuses was that I could simply shift weight from foot to foot on the short one, where as I needed to sometime get out of my straps to shift weight to control the pitch on the longer one. In the end, the longer the fuse, the more stable the ride and less susceptible to pitch input the shorter ones have.
Front Wing: This is the cornerstone of lift. The location as to where your feet/mast base is in position with this will determine how easy it is to get the foil flying. Since they are in different sizes, the larger wings provide more lift, the smaller ones don't. For easier foiling, you want to select a size that provides a little angle of attack (think stalling with an airplane). The faster you go, the more lift you get, and the stability goes down the flatter your foil becomes in a horizontal line. So, want to foil in lighter winds? Larger wing surface area. Stronger winds, less wing surface area. I weigh 80kg riding a 800cm wing and get lift with 11 knots of wind on an 8.0 sail (I'm at 6000ft of altitude).
Stabilizer (Rear wing): I wish the community would stop calling it a rear wing. It's not. It is a horizontal stabilizer, and provides the lift guidance and angle of attack for the wing of the system. So the smaller the stabilizer, the faster you can move it down and up in the water. The larger ones require more input. These physics change a bit as the fuselage length comes into play. For example, I used the same 800cm wing from my GT setup when I put the Race (115cm) fuse with the 255 stab. If you want a more stable input on pitch, you should go with a larger stab or a longer fuse.
So what does this all mean? Well, to begin with, it helps with what you want to do, where you sail, and your level of foiling. First off, I wanted a foil system that was modular. Something I could start with and buy components to tweak the ride, conditions and ability. Starboard does a great job by creating 'kits' or 'configurations' by providing a modular foil platform. After foiling my arse off this year from a beginner, I can now make foiling jibes (I'm about 5% successful). I'm seeing constant questions about where to start, what foil to get, etc. Hopefully this helps.
As for beginner foilers: You may want something you can learn on while going slower, or with less wind. I recommend the 85cm foil mast, with a Freeride (1100cm-Wing/500cm-stab/75cm-fuse). Or maybe start with the Race configuration with an 85cm mast. If you can afford it, go straight to the carbon mast, don't buy aluminum. Not only is carbon lighter & corrosion resistant, but it is less susceptible to permanent bending.
If you have larger waves/swells to ride over, the longer masts will help a lot through the troughs (Valleys) between waves. You definitely notice the foil slipping sideways in the troughs. Running a longer fuse provides better stability, but I found I had to move my footstraps forward & mast base forward to find a better balance. You'll notice a difference in where the wing (Center of lift) is relative to the different fuselage's out there. 75cm: everything needs to be back a bit. 115cm, move things forward.
When learning, the Sam Ross Videos seem to be spot on. He has this pretty well figured out. What would be nice is if he showed mistake videos and how to correct them. I would also like to see him discuss board setup based on where the foil surfaces are in relation to foot straps.
Good luck! Hope this was helpful. Otherwise, flame away! :)