I'm pretty sure the pain in the Achilles is due to my first ride on the fix, in which I foolishly tried to resist the pedals in a crappy way that stretched my Achilles a terrible way. Don't do that anymore, and after a long ride today it feels a bit better, just tight.
As for my knee pain from just having the balls of my feet on the pedals, I think its due more to the nature of my ****ty knee and less with the height of the seat. I'll give a lower seat a try though to see if I can manage the clip pedals.
I like the idea of clipless pedals, but I'm going to be using it a lot to get to class and want to be able to wear my regular shoes. Will be walking around a lot without changing shoes.
I will be going easier at first with the fixed. I've been riding the same gear ratio as I have now on single speed for a couple months doing about 50 miles a week(mostly commuting). I'll be reducing that by about half for a while.
SO if adjusting the seat height doesn't help with my knee on clip pedals, back to my original question do you think its better to use bigger platform pedals as opposed to using the smaller clip pedals without the clips? Thanks!