If I was you I would've transferred the water from the 46 to the 65 as well as ornaments, substrate and filter. Than you would've had a decently established tank to temporarily house the bass in. Also you haven't said how big the Pbass is or whether you plan to upgrade again as the 65 is still too small to house the bass long term. From what I've heard(haven't kept a Pbass personally) they grow at an exceptional rate and will probably outgrow the 65 in less than a year. You've put yourself in a bad position and my best advice is to keep the bass in the 20 as I think during cycling your more likely to lose him. As well as try to be better prepared for a fish you want to keep before hand as it saves you and the fish unnecessary stress.