no no no, don't dispair.....
regarding jfets in particular..
if I can offer a tad more encouragement, can I suggest/recommend you read(or re-read if you already did) the OM and the service manual for the first watt F3. It's a good intro to jfets from a crossover perspective.
I beleive Nick built an F3 back in the day as I have a memory of pointing him to the loveltech jfets. I don't have any memory of his findings on the results though....perhaps they weren't so positive?
I can send you copies if you can't find them.
In respect of jfets as front end contenders there is also the profet amp ideas which led to the F5 and the burning amp stuff.