Suggestion?

1965 225, on a test stand.
Well I've got the cam break-in period accomplished as per instructions by Hughes Engines. The break-in was done using "only" single valve springs. Now for the "suggestion." I'm trying to install the required "secondary springs" (inner) using the tool I have. I cannot compress the springs enough to install the keepers. I've got the valves held shut with compressed air and spring removal was easy, but the installation of the double springs "ain't workin." I sure don't want to remove the head (I will if absolutely necessary). I'm open for suggestions. This is the tool I'm using.
Norm

View attachment 1716418609
Those type of spring compressors are junk. I went through 2 to do both heads on my 318 with basically stock springs, no way you could do double springs with that type of tool.