Ha! No need to apologise and you know we're close to being in violent agreement. I wasn't suggesting everyone should learn to foil wing on 8' SUPs. What I said was that some board length has benefits to beginners which are often lost in everyone's desire to go small (reread what I wrote!).
Your last post kinda proves the point. You had to learn the right technique or you wouldn't have got anywhere. I've heard of quite a few people 'getting nowhere'. Now that could be for many reasons, but a in some of those cases they were on too small / short a board and have said as much.
You recommend mid 6' length as a max. I've learnt on something a bit longer, and don't feel like it's done me a disservice at all - even in 30+ knots, would you believe. I've had loads of fun, don't feel like it's held me back, never really struggled to get foiling, and have now reached the point where I'm after something smaller (5'6) but that's after getting a real solid foundation.
I suspect my board pumping technique is pretty terrible, and initially might not get foiling as quickly on the new board. But I'm also confident that it won't take me long to grasp because I've got all the other skills in the locker.
Peace!