Assuming that there are ribs inside to hold the film from laying flat against the inside of the drum, and that solutions can be poured in and out quickly, you should be able to use it for developing film. If there are no ribs inside, I'd recommend cutting a piece of plastic window screen the same size as your negative and placing it between the negative and the drum. This will help liquids get behind the film, which will aid in clearing the antihalation dye layer. Note: The negative goes into the tube with the emulsion toward the center and away from the outside of the drum.
I use a Unicolor 8x10 print drum on a motorized base for developing 8x10 film. I use 500ml of diluted developer. Check the capacity of the developer you're using to make sure enough raw developer will be in 500ml of liquid. (Better safe than sorry!)
Time reduction will depend on the film and developer that you use, but in my experience generally falls somewhere between 15% and 25%. (You'd have to do actual film tests with each film/developer combination to nail an exact time for your own methods, but 20% is probaby a good place to start if you don't want to do testing.)
Since you won't have a motorized base, there are a couple of things to keep in mind when you're spinning your tank. First, change directions. My Unicolor base turns somewhat past 360% and then reverses. I don't know the actual amount it turns, but there is a slow progression of which side of the drum ends in the "top" position on each cycle, so it's not anything into which 45 degrees is evenly divisible. (If you used 450 degrees per cycle, the film would end up in the same position every eight cycles...and you might be risking some sort of drag marks.)
From memory, I think it takes 5-6 seconds for the drum to spin as far as it will in one direction before reversing. It's a slow, steady turn.
If you're going to be spinning by hand, you might consider placing the drum in a dishtub with a few inches of water in it. (Try this without film to see how it works for you. The drum will sink with the developer in it; you don't want it to sink so far that water gets in but you also want to make sure you have enough liquid in the tub so that the tube doesn't scrape the bottom of the tub.) You could also lash something together using small wheels on which the drum could rotate...I think Jobo sells a base like that for manual rotation of their drums.
Finally, keep an eye on eBay...the motor bases turn up a lot and are very inexpensive. I think I paid US$25 for a base and an 8x10 drum. Best investment I've made for developing film, as it takes away many inconsistancies from my film development.
Best of luck to you.