I thought I'd post back in case other people have the same question in the future.
I listened to the advice earlier this year so prioritised a UHC filter from Astronomik and it made a huge difference viewing nebulae. I will get an OIII at some point too.
I also got a GSO coma corrector for the dob and the 30mm GSO Superview went from an underused eyepiece to a favourite of mine so ultra wide doesn't seem so important anymore. That said I do need an eyepiece in the 17-18mm range to bridge the gap between 2.7 and 5.6mm exit pupils on the dob
