I find my 26mm fan P&C Platypus feels bigger than my Omega 48 boar, which is the same size as your Italian Flag Omega I believe, just with thicker bristle and a lower rent handle. This is mainly due to the splay of the "weaker" badger hair compared to boar bristle.
Hard to compare the two otherwise really. I love my Omega 48 and find it's the perfect size and backbone for me. I think 26mm is an ideal size in badger despite the lather hog tendencies. Backbone is completely dependent on loft / shape though. Get the lower loft if you want backbone but you will have to do more work to make a lather without the loft available to do the work for you - it's all a compromise and I find my Platypus loft a good compromise on that front, for a badger brush.
Personally, my frugality couldn't cope with a badger any bigger than 26mm - there is only so much soap I'm prepared to flush down the sink! I'm looking to go up to 30mm in synth though...
BTW my Platypus could be for sale if you're interested - that would allow me to get a couple of other brushes I have my eye on (including an Italian Flag!)...