I agree with Potholer that a steel maillon is a bad idea. For many cavers it tends to get opened so seldom that the one time you want to open it (like taking off your ascender to improvise during a rescue), you find it won't open. Plus a steel maillon will wear out the hole in the jammer.
I actually use an ordinary screwgate crab. I tend to carry my jammer clipped on with that very crab, with the foot bit of the footloop clipped into the same crab. That implies that I have to unclip the foot loop and do up the crab at every pitch, but it's never bothered me. I could carry another crab I suppose, but I grudge the extra grammes.
More recently I have sometimes caved French style with no safety cord at all, using my long cowstail to clip into the top jammer. This is ultra light-weight, but after trying it a few times I decided that the extra weight of the safety cord is worthwhile. I thought it worth trying since 95% of French cavers have their rig set up that way. Since I have a spectra footloop, I currently have a seperate safety cord. However, I have considered using a spectra safety cord (again toi reduce weight and bulk). I know this has no shock absorption, but I don't think half a metre of dynamic rope which has been dragged around a load of caves has much energy absorbtion capability anyway.
I don't see any particular need for three cowstails. Two have done me just fine for over 20 years of vertical caving. I do sometimes use my top jammer instead of a cowstail, mainly on sloping traverses. So that isn't because I need three points of possible attachment, but because I don't want to be exposed to falling back down the traverse.
Mark