Try these..
<kuid2:655957:2001:1> MRR: HO Scale Radii Guide01 18_42
<kuid2:655957:2002:1> MRR: HO Scale Radii Guide02 18_42
<kuid2:655957:2003:1> MRR: HO Scale Radii Guide03 18_42
<kuid2:655957:2000:1> MRR: HO Scale Radii Guide 18_36
They are ideal, are height adjustable too.