Haven't ridden a canard design but the reviews suggest that at least with the bigger wingset the Zeeko Spitfire shouldn't present any problems to beginners.
I learned on a Zeeko Blue and White (now for sale

) with a 90cm mast and strapless board with no worries and now progressed to the carbon version (1m mast), still strapless. I was foiling for decent length runs from my 3rd session onwards, and a shorter mast would have only made the first and second sessions marginally easier (getting used to riding around on the surface with a new appendage underneath), and then been a waste. As soon as you're on the foil the full length mast gives you more flexibility as you learn to regulate your height and navigate chop without ventilating the foil.
Maybe others with less directional experience take longer to get riding but for you Lambie with years of surfboard experience I'm guessing you could go straight to a full length mast...
P.S. I'm a big fan of the safety advantages of strapless foiling, especially for learning - when you start to lose balance, you bail, no temptation to risk ankles and knees trying to muscle it back. You just need to spend a few minutes finding the balance point for manoeuvring the board to a waterstart position with your back hand (and both feet) while keeping the kite at twelve with front hand.