Ah, interesting. Well, I don't know anything about Italian pronunciation (clearly!), and am not familiar with IPA either, so I can only help so much. The way I did it is the standard way to convert English sound perceptions into Japanese, but if you're decently familiar with the Japanese sound system, then I say go with your gut, but also look for examples. My first reaction to your attempt was just based on the fact that most of the people that come here don't really even know how the Japanese phonemes sound at all, so
Looking more closely, I can find actual examples of the name Raffaele being transcribed as either ラファエレ (as in Rafaelle Cutolo, the, uhm, crime boss) or ラッファエレ (as in Rafaelle Palladino, the football/soccer player), and nothing for ラッファレ, so whatever you feel is more accurate. I wouldn't personally use either ハ examples you gave, and can't find examples of them being used.
I can see examples of Grieco spelled a lot of different ways. グリエコ is one of them, so if that feels right, go for it. I still can't be sure exactly how you pronounce it, so I still think グリーコ or グレーコ might be viable as well depending on exactly how the sounds comes out as (and I prefer to minimize the sound variation in a name because it makes saying it smoother), but I say do whatever you think feels best.
Since the whole system is basically a work in purposely corrupting your name into a more limited sound structure, the whole thing is kinda flexible. There are a lot of common practices, but there aren't necessarily rules. I've looked up a few things in the past and found the same celebrity's name spelled several different ways by different people. So you've really got some leeways for stylistic choice, I think, as long as you're staying within the general guidelines of how things work and paying attention to present trends and things that are already established. For example, there's less wiggle-room if you have a name that's really well-known in Japan. My name is Andrew, and I've pretty much got to spell it アンドリュー whether I like it or not (I don't, I have trouble pronouncing it), because it's what everyone in Japan expects. That or アンドルー, but the other is more common.