can be mixed up and used as a slurry...either to kill the suction completely on very porous substrates or as a slurry coat onto substates to aid bonding of the render maybe a painted external wall...where the paint is sound. Expensive stuff...never used on a rendering job myself, you may well find its cheaper to use something like weber rendaid does the same job as above.
Yes but it would be an expensive altenative to other methods...for example External PVA to kill suction, wetting the wall, a mechanical key to aid bonding. If the money is in the job SBR will probably be your best option.
Usually applied with a Tyrollean Gun and I beleive if its for bonding render to the wall...render must be applied when SBR is tacky.