aftermarket balancers- custom pulleys?

I'm looking to get another harmonic damper for my 273, but as I've discovered, some balancers are a different overall length- necessitating custom v-groove crank pulleys. A machine shop(Dyers) I talked to said this is commonplace, but I've already got a blower pulley($200) made up to the stock balancer dimensions.
I was looking at the Romac balancer, but can't find any info on the overall length. Any info out there on what fits/doesn't fit with the stock pulley? I'll go first... The CAT "fluid" damper is 1/2" longer overall, as well as 0.002" too small for the snout.
Also, would it weaken the balancer too much to have it redrilled for the "odd" pulley bolt pattern that the 1965 273's had? Opinions...