No real knowledge but I had an EZ-1 sx and while killing time in a forum the 16 inch wheel was thought to be a real speed reducer.
Good for torque but cutting top speed by a considerable amount..
Something to consider.
I did convert my EZ-1 to a 20 Inch front wheel using the fork off the EZ-Sport. To avoid cutting the Sports slightly longer neck I shimmed it.
It worked well and did what I wanted, bending the fork to correct additional extreme wheel flop was simple. It was about a 3" ark placing the
Axle point between 2 and three inches forward of the original pos...
Many factors to consider doing this... A 'Mid Drive system' will let you use all the cassette gears for even MORE speed and power, Yes the Mid drive would be more complex and expensive, But as with most things In Life, 'You Get What You Pay For'
Is Mid Drive worth the money ?
For Flat land riding, probably not,
For Hill climbing power, being able to down shift that power for a steep hill, also for all out performance/speed, possibly, speed cost money, Say 3 times the cost of a basic Hub drive system...
Then I moved on to this:
After applying the EZ-1 money to this like new used (50 miles IF that)Tour Easy LE model I was in the TE $450.....
And Sold my like new 6 year old EZ-1 for more than I paid for it new
They were only $500 back In 2007
My EZ-3 stock and how I will go Electric with it one day:
OP, Hang your batteries under the seat for better handling....
20 MPH with the 16 Inch wheel,, gonna take more volts,, 48 I would think
a 20" wheel hub motor combo could probably do 20 on 36 volts
a geard motor right ?
48 Volts and 600 watts In a 20 Inch wheel got this man 26 mph....
http://www.electricbike.com/recumbent/
So you could hit 20 with a 16 Inch wheel, maybe...
Look Into this stuff below, lots of tech there..
http://www.recumbents.com/wisil/e-bent/default.htm