why would you not use a pedal? it's exactly what you want/need. an od boost will do pretty much exactly what you want.
an 81 has silly output. if it doesn't have enough there's something wrong. plus it basically has a preamp in it, which again makes it strange that you're not willing to use pedals, but are willing to use a pickup which more or less has a pedal in it.
Using a boost would also give you the option of being able to pick a pickup based on its tone etc. rather than just its output. So you'd have a lot more options.
i mean it's your gear and your call, you can do what you like, but if you ask me you're shooting yourself in the foot for no good reason.
"hey doc i want to cure this tonsilitis but i'm not an antibiotic guy" is sorta what you're saying :lol: