Sounds as if you are too low when you are on the spikes, body is just not used to pedaling in that position, and you are putting out way less watts. Your using different muscles in different ways, for the first time.

A lot of guys slap some bars on their road bikes, and end up going slower.

I ride my TT bike every other ride, it sucked at first, sore legs, back, hell I needed a chiropracter after every ride, but now. It feels great, and is noticibly faster over any given distance.

I wouldn't corner on the spikes, use the bullhorns.... how did you crash by going around a corner?

You are going to be less stable on the spikes, because you have almost no leverage, and becuase your Cg is farther forward over the front wheel, plus... your not used to riding the bike this way. Its like learning to ride all over again, kinda..

I had a skipping chain when i first built this thing, and it skipped under load, when I was on the spikes, and I almost wiped out, now I feel more confident, but it is still less control able.