On May 14, 12:35 pm, Jose wrote:

Ask your maintanance guy. A tach check may be part of the annual or the
100 hour. If you have access to a strobe and an accurate flash rate,
you could use that on the prop too. Use a partner, for obvious reasons.
"Kids, don't try this at home!"

A good question to ask. I called the flight club and spoke with a
young CFI, but knew I wasn't going to get a good answer when he asked
me what I meant by the tach reference speed/time. I'll have to follow
up in person.

Now, do you actually have a choice, per flight, as to what method you'll
be using (tach or hobbs)? Can you decide after the flight?

Unfortunately, no. That would be great, though, wouldn't it?