All of the above, plus the best thing to add to an eight cell model is two more cells! Even if you have to keep the amps down because of motor considerations, adding 2 x 2oz cells to a 48oz model is a percentage weight increase of just over 4%. The power is hiked up around 25% if you reprop to maintain the amperage to ensure your motor survival. Even the lowly Mag Mayhem does fine on 10 cells, as long as you stay at 25A max.
The main difference between an AF and a ferrite - I've got an AF035G that's been running on 10 cells and 30 - 32A for five years or so, pretty much continuously. I looked at the brushes last week - still there.
Scott's right about funfly models - first off, do you want that envelope? They are fun to flit around and mess with, but very few of us will ever aspire to fly them like Gary Wright and a very few others. The Embat is classic pattern on the small size - it will pull huge round maneuvres and really long rolling maneuvres, but really is as little wood fuselage as can be decently wrapped around a direct drive 300W+ brushless / 10 cell package.
If you can track down an Embat plan, it is about spot on for this level, in terms of size, 'numbers' and weight/loading.
One of my models for next year could look a lot like an Embat wing on the bottom of a slimmed off 'pylon racer' type fuselage - a glow powered racer, not the electric sort.
When you do it - do the first one real light and well made, but with a basic finish and low in fiddly bits. If it works, tart it up plenty and go fly while you do an even better one. If it doesn't - less time and effort lost