On the client, “\citizen\common\data\gameconfig.xml” has various pool sizes. It says RADAR_BLIP is 1800. Testing in-game though I was only able to get 99 blips.
If you were gonna be able to adjust the size anywhere I really think it’d have been that pool size, but it doesn’t even seem like it’s near accurate to begin with. Sounds like you’re gonna have to get crafty with how you use your blips.