OK so Im considering new rigid forks - but confused at what different offsets mean. Most have similar A/C measurements (either 485 or 490mm) but offset varying from 47mm to 55mm
I plan to use different wheels with tyres between 2.4'' and 3''

Not sure what this will mean in real life in terms of handling. Anyone knowledgeable that could help explain?

This might be helpful: https://www.mbr.co.uk/news/fork-offset- ... ail-342679

Fork off-set greatly effects 'trail' which can make or break a bikes handing and alter its character ... the cycle world used to get confused and call 'off-set', 'trail' but luckily, the monkeys at the magazines / websites seem to have a grasp of it now

Do you know the off-set of your existing forks Mart?

Mmm a good read but after reading it Im not really any wiser. I have had some previously that were Travers Prongs (early design QR versions) so not sure If offset has changed with new ones. Looking for new ones that need to have 15mm axle and in Boost width (then I can swap wheels with new sus fork I have)

Not many about ... my list so far has only 3 options

Niner RDO Boost - bit spendy at £600 (51mm offset)
Travers XC Prong Boost (47mm Offset)
Kinesis Maxlight Boost (55mm Offert)

Mart - in very simple terms ... if you fit a fork with increased off-set and everything else (AC length, head angle, etc) remains the same, it will reduce the amount of trail. A reduction in trail will 'quicken up' the steering.

Nothing happens in isolation but that will be the most noticeable difference but how noticeable is hard to predict.