if the magic chain length scheme does not work out,
yea any old RD will do, just screw the limit screws in so it centers over your cog.
Maybe washers and longer bolts to hold the pulleys since the 1/8" chains are wider.

there are rigid locking single pulley mechs too
made for those many for single speed conversions..
since the chain tension does not vary.
the slack just needs to be taken out.

Given an option you should go for the black hub, for the anodizing treatment.