Yes that would work just fine, but parachuting it would be a better method if you just want to take the crushed powder orally. If you don't know what parachuting is, it is quite simple. Crush up your Oxy nice and fine. Then, rip off a small corner of a tissue. And I mean small. Put the crushed Oxy onto the small piece of tissue, and roll it up into a tight ball. Take this like a pill.
Im surprised the high only lasted you 30 minutes when you snorted it. When I was into Oxy, snorting an 80 would keep me feeling nice for a good 3-4 hours. Sure, the initial "rush" (and I use that word reluctantly, but for lack of a better word it will have to do) will wear off kinda soon but I still will be glowing for a few hours after that.
Orally is honestly your best bet though, when it comes to Oxycodone. The BA (bio-availability) is a bit higher when taken orally, as opposed to snorting it. As for dosage, you said you take percs regularly, and they are the same thing as Oxy. Oxycontin = oxycodone, Percocet = oxycodone. Same chemical in each. So just take your dosage for percocet, and translate it into Oxy.