I've been using a booster of sorts ever since I've used telescopic sights. Reason is that i shoot right handed but my left eye is dominant.
My boosters are just camera close-up lens/es in a home made eyepiece adaptor. It takes a but of faffing around to get the best distance from the eyepiece but it does give me a much clearer view and reticle image.
The downside is that there is now virtually no eye relief although thats not much of a problem on a PCP.
Like this ....
Colin.