I've used similar valve spring compressors with good results. You have to support the valves with something soft while using it, because the locks can be very difficult to jar loose. Especially on an old head.
I have a small K-D spring compressor, and also a large C-clamp type you could borrow.
Click to view attachmentClick to view attachmentThe small one is slower, but more controllable. The big one can be a little awkward, but is quicker. I can either ship them or meet you in Tukwila or ?
@jsaum