I might have similar type of feet. Mine are narrow with low instep and finding a good fitting shoes is difficult. 325 is an okay fit, but not perfect. In the C&J Brussels store I tried loads of different shoes and the 379 was the best out of all. Maybe you might consider that as well.Now it got ever more confusing than before for me.
I had a chance to try Conistons in Berlin and it felt better than my Snowdons on #228 that I own what I remember but it's 2 years back and it was only a try on in a store...
I am discussing a GMTO/MTO option with Alex on a black derby shoe on #375 as she recommended that last for me.
I have just received a pair of Chilterns and their fit is magnificent for my weird feet. Nothing else than Chilterns are on that 224 last however.
Hope this helps.
Btw, the Brussels store has very nice service. I recommend it to anyone visiting Brussels.