[Roadsters] Valve Spring Compressors

[MH]

I'm trying to use a valve spring compressor to remove the valves and springs
from a 1600 head. The head is already off the engine and sitting on the
bench.
There are several types of spring compressors for this task. I'm trying to use
the kind that has "little jaws" that are inserted in between the coils near
the bottom of the spring and then a knob is turned on the other end to
compress the spring. It compresses the outer spring, but it looks like there
is no compression of the inner spring and this is keeping the retainer and
collets still locked onto the valve stem. Any advice, tricks, or tips for
using this tool or should I get the C-clamp type? It looks like that works in
a different way and would probably do the job a lot easier.
As usual, thanks in advance,
Mike Hudson  '67 - Stroker / 5-speed