I would research both ideas first.... I think it might be too much at one time. I understand why you want to use what you have but in container gardening space it tight and there is not a lot of places for strong ferts to dissipate. The smell might also be an issue (indoors). I would use the shake and feed fert in a bottle. It's not expensive and it's time released. Just follow the directions, no fuss or muss!Looking ahead---
It occurs to me that tomatos are heavy feeders and will need fertilizing while in the house. I would prefer to use something I already have, like rabbit pellets. Can I collect the rabbit poos and then make a tea? Or just mix it into a slurry and pour on top of the 5 gal pot?
I would need to start saving the pellets now instead of dumping out on the lawn . . . .