Quote Originally Posted by TheFatHousecat View Post
I would be perfectly content to have marks abolished and for us to be able to exchange old marks for seals at a 100 marks = 1 seals rate.

If they actually plan to continue the gain/use of marks in the future then it would probably be best to have a GC-style gear set per guild that you can buy with marks. Maybe not a set that you'd want to wear as BiS, but some pieces would be a part of hardcore sets while others would simply be a nice alternative to other similar items that might be more expensive on the wards.
I think this is fair or 1/50 ratio even. It would be my first choice. Second choice would be gil at 3/1 ratio at least.