theres pro's and con's to a plaster material being stronger/weaker ...but thats another disscussion.
As for micro cement well theres tonnes of them on the market and some of the systems are pretty good.....
for anyone interested you can kinda create your own micro cement,it will be more like a cement based venetian plaster,used for resurfacing old floors...and new alike.
read this use it as a reference
Skimstone
the products simplified:
the white powder is ....cement....yep its just cement they call this "hybridised cement " and sell it for about the equivilent to 80 quid for a 20kg pail ( yep no s**t )
the type1 solution is .....in this case is a damned good styrene based acrylic...go to the tile store and use the best acrylic admixture you can find.(you want high solids)
the aggregate is #70-#100 silica sand....or any other super fine sand you can find.....must be super fine.....even calcium carbonate would work.
mix it together in a ratio of about 2/1 or 1/1 sand cement....with the acrylic polymer
follow and replace the directions with material you have at hand ...and innovate....you will after mixing to a creamy paste ,have a product that will stand upto the weather ,try it on a piece of cement board ...and leave it outside....youll be surprised....tough as nails.