hmmm, if that means the frobhelper will still blink in and out of existence even if tdm_frobhelper_alwaysVisible is 1, then this is not really what I'm looking for.
Ok, I guess this needs some more explanation.
If tdm_frobhelper_active is 0, the frobhelper is never shown. Set it to 1, and it will be rendered in one of two modes:
1) The original design, i.e., automatic blend-in when near small objects, is activated by setting tdm_frobhelper_alwaysVisible to 0, which is the default.
2) If you want the crosshair to always show, independent of current context, you have to put tdm_frobhelper_alwaysVisible = 1. The frobhelper then behaves like a regular crosshair.
If you want to actively toggle visibility, you have to set tdm_frobhelper_alwaysVisible = 1 and add a keybinding that hides or shows the frobhelper via
bind [DESIRED KEY] toggle tdm_frobhelper_active 1 0
As a bonus, actively toggling visibility via tdm_frobhelper_active will also use the existing fade in and out routines, so it doesn't pop in instantly. However, you will want to set tdm_frobhelper_fadein_delay to 0 and reduce fadein and fadeout durations, for more responsiveness.