If we didn’t want to invest in the vacuum chamber and pump, would it work if the blanks were weighted and submerged in cactus juice for say a week or two (like the Minwax hardener)?
You may get descent results submerging the blanks and letting them soak for a week or so. I have done testing on pen blanks where I did some with vacuum, some with pressure, and some just soaking. The vacuum blanks did the best of course, with a 300% weight increase but the soaked blanks still had a 200% weight increase. The pressure blanks did not do any better than the soaked blank. If you are getting descent penetration with Minwax Wood Hardener with that method, then you should get similar penetration with Cactus Juice but the results will be much better since it hardens to form a hard acrylic and does not have any volatile solvents that have to flash off, leaving the little bit of resin behind like Minwax.