I copied the following data from Redding's web site. It may well be worth your time to make an email query to see if they would do a comp seater for your application.
Their emaill address is as follows:
Custom Made Dies
Custom made dies are not kept in stock and are made to order only. Our Series “C” and Series “D” listings contain many obsolete and wildcat calibers normally considered “custom” by other manufacturers. We try to maintain limited quantities of factory inventory on these. If you do not find the dies that you need after consulting the die caliber reference charts on pages 13, 14, 15 and 16, we can usually custom make them for you.Please keep in mind, the die reference chart is only a partial listing. We have made custom dies for hundreds of chamberings that are simply too numerous to list.
Some cartridges with a very unique design and/or unusual shoulder angle may require a tooling and engineering charge to partially cover our expense for making up special tooling. In the event such costs are required, they will be quoted separately. To get a firm price quote, send us your chamber reamer drawing, including all dimensions and the shoulder angle.
As an alternative, you can simply send us three (3) fired cases from your chamber for examination on our optical comparator. Package them carefully to prevent damage in transit, and do not forget to include clear instructions as to exactly what your needs are, i.e. dies to form the case, full length die set, neck sizing dies only, etc. Your fired cases will be returned upon request. Because of the nature of work involved in making custom dies, advance payment is required with the order. No COD’s please. Delivery usually takes from 12 to 14 weeks after your order has been received.
Custom Two Die Sets $ 126.00
000w/optional tapered size button $ 132.00
Custom F.L. Sizer or Neck Sizer $ 83.00
000w/optional tapered size button $ 89.00
Custom "Type S" Neck or F.L. Sizer $ 108.00
000w/optional tapered expander $ 114.00
Custom "Type S" Neck Die Set $ 225.00
00w/optional tapered size button $ 231.00
Custom Deluxe Die Set $ 195.00
00w/optional tapered size button $ 201.00
Custom Three Die Set (straight wall cases) $ 141.00
Custom Seating Die $ 72.00
Custom Taper Crimp Die $ 61.50
Custom Form Die $ 61.50
Custom Trim Die $ 75.00
Special Price Group (*) $ 144.00
Special Shell Holders (*) $ 15.00