Why are you using rods?
Are you just wanting to use the Moretti rods because they’re softer? (Moretti = 104 COE) It seems to me that using rods would be more expensive than using regular sheet glass. The effect sounds like it would be nice, but it seems like the rods will flatten out some during the multiple fusings, so I’m not sure of the advantage of using them. I guess if you were just slumping them and had a lot of control over your heat, they might end up more rounded than sheet.
Boro would be stronger. With a COE of around 32, it would also be more heat-resistent. I love the way that colors of Boro react, so they might be some interesting design results there. But last time I bought Boro rods, they seemed much more expensive than Moretti.
I also fused Moretti sheet, millefiore elements, and some lampworked items once, and used the same firing schedule I’d been using for System 96. My project came out in a big blob…I should’ve used a specific firing schedule for Moretti because it got way too hot. I’ve never seen a fusing schedule for Boro.
Will your bowl be more decorative, or for heavy use?