The bare minimum for successful production of estrogel is a millimeter scale, an airless pump bottle for easy dispensing, and weighing paper to easily dump the powder into the bottle.
\(G:=\) The capacity, in grams, of hand sanitizer your container can hold.
\(C:=\) The desired concentration of estradiol per pump (0.5% or 0.005 is recommended)
\(Y:=\) The amount, in grams, of powdered estradiol you'll need.
Then, $$C=\frac{Y}{Y+G}$$ and after some algebra, $$\frac{CG}{1-C}=Y$$ You will also need 3% grams of \(G\) in orange oil/d-limonene, which is a penetration enhancer.
Suppose \(G=45\), \(C=0.005\). Then $$Y=\frac{45*0.005}{1-0.005}$$which comes out to $$Y \approx 0.226g$$ of powdered estradiol and you'd need \(0.03 \cdot 45 \approx 1.35g\) of orange oil/d-limonene.