New to grafted cacti - Rootstock question -

[Old Lefty]

Greetings from New Jersey!
We are awaiting a small grafted ‘Echinocactus’ with delivery expected in a few days. At this point in time the species of the rootstock remains unknown, but will try to post a current photo with this post.
The questions that we wanted to ask, is there any advantage to having a ‘short’ rootstock as shown in the photo? Most photos of grafted cacti show a much ‘taller’ stock.

Another question, should the entire plant be cultivated as if it were an ‘Echinocactus’ species requiring less watering and mostly an inorganic substrate mix or mainly what the rootstock requires?

Thanks for your input!

[Hanazono]

is there any advantage to having a ‘short’ rootstock as shown in the photo?

I am not sure the intension of supplier but A short parmanent stock turns to a woody structure in future and yo can bury it in soil.
The woody stock can be alive years in soil.

should the entire plant be cultivated as if it were an ‘Echinocactus’ species requiring less watering and mostly an inorganic substrate mix or mainly what the rootstock requires?

The growing condition of a normal grafted cactus should meet to "stock" but in case of short stock should be:
Light: meeting to scion
Soil: meeting to stock
Watering: meeting to stock

[Old Lefty]

Thank you so much for your reply! Very interesting, will write this down to keep it permanently.