Toolman;
 I think you are better off using the rubber boots as the leather boots can be a bear to lace on and don't ususally last that long in the sun. Plus once the lacing comes loose, the boot must be re-installed. My 2 cents; Get the rubber ones and tape them on. 
I'm using the Taylor-made rubber boots from Defender; see:
https://search.defender.com/?expression=spreader%20boots&s=1&Trigger=ac
(Might add your location to the signature)
Bill
 

Bill:  Did the large boot fit your spreader arms?  I bought some years ago that were a little to small and challenging to install.
This is very timely for me as was just thinking about having to get them ordered.  My boat won't go in the water for 1.5 more weeks.
I agree about the rubber over leather - tried them once - they looked neat but didn't last.  Thanks

Harold;
 I Think they were the medium size (almost sure of it)  but you should measure the diameter of your stays and use the link in my previous post to check. The link I sent you out lines the various spreader and wire size;
https://search.defender.com/?expression=spreader%20boots&s=1&Trigger=ac
 https://www.defender.com/product3.jsp?path=-1|118|2358491|2358503&id=1004606
Probably too large  is better than too small even if you must cut them down to size. If you buy them from a local supplier, you can always return them.Take a look at the spreader and try to estimate the size you'll need. I'll be down at the boat tomorrow and see if I have it in my notes.
Bill

Harold;
 Checked today and my notes say that I used Taylor-made 'medium' size boots. 
Bill

I purchased the leather ones from Catalina Direct and installed them last spring.  Instalation was straight forward, leather came cut to size with stitching holes punched.  So far they have held up very well and we are happy with them.

I used the large size from west marine and they fit fine. Used tie wraps to secure and then a few wraps of rigging tape to cover the tie wraps. 

I have the leather spreader-boots from Waterline-Design fitted and this is perfect, easy fit and proper secured with velcro. 
Also I ordered initial the Catalina-Direct offered leather spreader boots but these are not of this era anymore - with needle and yarn to fit....

I have been seeing this new type of boot online and I really like how they look and how easy it seems to install. Are they still holding up? I need to replace mine soon. Thanks.  

Tom; Well the spreader boots did not last more than three years down here in the Florida Sun. We replaced the boots with wheels by Harken. These are little wheels that are about two inches in diameter and snap on the stay just above the spreader. The sail falls against the wheel and slides around the spreader. Works a lot better and holds up longer. I just don't know what they are called (anybody ?) but I got them at West Marine. Just wish we could still post pictures but I'll bet that if you went in to WM and explained it to them, they would know what I'm talking about. Try these;

https://www.westmarine.com/buy/harken--chafe-protectors--453415?cm_mmc=PS-_-Google-_-GSC%3ENonB%3EProduct%2520Type-_-453415&product_id=453415&creative=108421553284&device=c&matchtype=&network=g&gclid=EAIaIQobChMI6sfuwYOe6wIVC4-GCh3i-wu5EAQYAiABEgLo8PD_BwE

Thank you for the quick reply. I will try those wheels.