Just broke out the scales: Regular Spikes weigh in at a sturdy 53g and the Ti versions a slightly more svelte 33g. And for the record the Ti/Ti Polarized crosshairs weigh in at 23g.
Regular C5 Spike
Ti Spike
Ti Crosshair
some extras
I also tried for a side by side shot with the gascan but none of them came out very well, I need a bit more room (and less clutter!) If no one else can help out with these I'll try and reshoot them.