is TE probe needed?

My homebuilt self-launching sailplane is getting very close to it's
first flight. However, to make a long story short, I don't have any
good place to install a total energy probe right now. I have an old
variometer that I was planning on starting with, if it still works.
Otherwise I may need to get a new variometer for it, like the B400 or
RAS-V1000. But I see where they require a TE probe. Can these or
similar varios be used without a TE probe and still get useful
results, maybe just hook it up to the static system? Or are there some
small low cost varios that don't need a TE probe?

Thanks in advance,
Jerry Booker
www.jsoaraero.com