I've been making my own spikes for over 15 years using the Stephen Hatch method with 0.015" steel piano wire (avialable from the K&S stock at hobby shops). It's simple and easy, as well as very cost effective. SEE: http:coslar.us/ties_rails_spikes.html
Many N scale folks using C55 (and C40) rail also use the Proto87 Stores chemically etched stainless steel spikes. These are smaller than my own 0.015" hand made spikes, have a reverse taper for grabbing in the ties, and don't require a special sub-roadbed since they actually hold with just the ties. Usual installation is with tweezers as these are small but very effective. Also see links from my web page.
Don't go for the Micro Engineering "Micro" spikes. They are soft and usually most experience about a 30% or more bending when installing. Some have had success with the ME "small" spikes, but these will be a little large for N scale trackwork used for your HOn30.
-ed-
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-ed mccamey-
COSLAR RR -
http://www.coslar.us/NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.