You can have up to four minis installed on loan each subject to a one off upfront charge and all under by one single Q monthly Multiscreen subscription However only two minis can be used simultaneously on all 2 TB boxes and the 1 TB UHD Main boxes to watch Sky Q content. The original 1 TB non UHD box (32Cxxx) only permits the use of one mini at a time. If Sky Apps are already being used on some of the minis these will not normally be counted as in Q use and therefore can be used in addition to the above limits. See the following link for the Versions of main Q box referred to above. https://www.sky.com/help/articles/sky-software-updates. Subject to the above limits Sky Q minis can be used completely independently of the main Q box and the same or different program or recording can be viewed on each Q box. Even if viewing the same content it is completely independent and can be viewed at the same or different point. Minis can do all the features same as the main Q box and can set or delete recordings on the main Q box hard drive. There is one single storage area on the main Q box with no profiles and no indication of which Q box has set a recording. (Unlike Sky+HD Multiroom which has independent storage and planners). It should also be remembered that minis cannot view UHD recordings or content.
The only time you can use 3 at the same time is if one is being used for Streaming apps such as Netflix or Disney + ( this needs to be the 1st one in use)
There is no way round this as it is a hardware limit of the main boxes
