I've made it ....
Luisa, I'm glad you had a success with this amazing roast, although apparently not without some angst ; )
Here are some observations:
This recipe depends on that low 200F roasting temperature. A higher temp doesn't get the succulent juicy results and it also burns the honey glaze, both on the roast and in the pan. I once tried to hurry this recipe up, and it protests if you do. I learned it just takes its own sweet time to get the results.
That said, the recipe is for a 3-4 lb. roast and you used 5lb. Did you increase the glaze proportionately? As you discovered, the roast does not give off a lot of juices. I'm not a scientist, but from my experience, I believe the low roasting temp melts the juices slowly into the roast (that's why it's so unbelievably juicy on the inside), and the honey glaze also seals them in since it makes such a wonderful candied crisp crust.
Anyway, the glaze as you discovered gets quite thick in the pan. The butter keeps it fluid. With the larger roast, and the longer cooking time required, you definitely needed more glaze as the recipe amount would have been used/dried up. I've made this with a 10lb boston butt and I tripled the glaze for that amount since it was going to be in the oven for 7 hours.
Towards the end of cooking for that long, I sometimes add a splash of stock to the pan if the glaze completely reduces and sets up. Should have mentioned that.
And the sauce. This is truly one of my favorite sauces for a roast. It is sublime. I don't know which is better, the roast or the sauce! LOL
I'm certainly glad you enjoyed the recipe and sorry I didn't give more tips so that you could avoided the worry. To anyone else, I hope you'll try this recipe, it is a classic. We usually save this for company, that's how wonderfully amazingly good it is.