Oral BA is extremely high so "best" to swallow but can also be snorted if you don't mind sniffing half a metric fucktonne of filler, clogging your membranes up and wasting precious mgs. Some find the placebo high from snorting anything to have more subjective effect than plain ol' oral dosing.
As for dose, completely depends on your tolerance. I find 30-50mg to be a reasonable (if kinda mild) dose with no particular tolerance (but long history of prior opi use and addiction) but will easily get through 300-400mg a day when it's to hand. I've also heard of plenty people for whom 30mg would be waaaaaaaaaaaaaay too much. Given you also have extensive opi experience I'd suspect you'd be nearer to my kinda doses but - frankly - expect to be disappointed. It's nice enough but massively overrated in my opinion.
To be clear, when I say I find 30-50mg without tolerance to be pleasant but kinda mild that is for me with my personal history of opi use and abuse. It is almost certainly far too much for folks without extensive history of opies. Opiate naive folk would perhaps be better sniffing half a 10mg capsule and see how it goes before delving any deeper.