I've never found the GI value of any real use in practice. I just look at the Total Carbs figure and work out what I'm actually having from the portion size.
I completely get your frustration managing carbs without clear GI info can feel like guesswork, especially when two “healthy” breads can affect blood sugar so differently. Having the GI index on packaging would make things so much simpler.
I checked high and low GI products in the year after diagnosis - only in meals as I only have a simple meter - but it made no difference at all. Not once did a low GI variant produce a lower blood glucose level than the 'normal' one.
It was my GP who told me not to totally exclude carbs from my diet because they were needed.So go figure !
I think we can all agree that low carb is the way to go though.