In some European countries, where there are lower power limits than here, there are classes for low power target rifles to be used in FT.
While the power of your 66 is low there is nothing stopping you adding a scope and using it. You will probably find it would be better for HFT with it shorter maximum distance. I have had several FWB Mod300's and have found that with a scope added they are surprisingly useable at knocking down FT targets out to 55 yards.
I would be inclined to suggest give it a go and if you like the sport save up for a nice rifle specifically for the job.
People who have been there focus on the fundamentals. People who sit at keyboards all day focus on the trivial and inane.