This mod is a standalone updated version of the original Gift Horses Mounted To The Max mod. It allows players to assign up to 50 horses to 50 followers. This mod can be used on any level computer that can run Skyrim SSE or AE. However... the more followers you have riding horses, the more taxing it will be on your system. Tested with an i7 13700k, 32G 6000 mts ram, Samsung 980 NVME SSD, and an RTX3060ti FE, it handled 30 followers riding horses with no problem. I usually only have 15 followers or so because it gets crowded in some cave intrances, and I have to fus ro dah them out of the way...Anyway, you don't have to use all the slots for different followers. You could have say, 5 followers and give each of them 10 different horses throughout your playthrough. Sorry, only one at a time though. You can check out the full info and media and the posts on the original mod page. Its a simple, no load process  to assigh the horses to the followers. See the vids  demonstrate in real time exactly what to do. This mod is for multi follower mods that have riding packages for the followers but no way to assign the horses to them. 
Do not use this mod for vanilla followers unless they are added to a multi follower mod. For vanilla followers not included in a multi follower mod, use my mod called A Gift Horse 1.1. It has the needed riding packages included. If you don't need 50 slots, you can use my Any Horse for Any Follower 1.3 mod. It has 8 slots each for horses and followers with the exact same functionality. 
This mod is a horse of a different color, so be creative and have fun.
Thanks
to djohnjarvis for the idea from Sofia the Funny Fully Voiced Follower 
to mitchalec for the inspiration and encouragement from Convenient Horses 
to fierymarigold for the beautiful horses of Swift Steed Stables 
to all the creators of follower mods that are so useful
to all of you that love the game.