Help ! Frankenprey/whole grind balancing

[infernalancestry]

New ferrent here, I have two kits that are almost three months old and they eat a LOT more than I expected.
I'm worried about being able to keep on top of making sure they get the correct nutrition with a Franken prey diet and I can't order whole grinds from mypetcarnivore as I'm based in Ireland.

There's a whole grinds site based here and they have a line specifically for cats that I was looking at but it seems to have an excess of organ meat and I'm concerned that might cause an overload of vitamins that they can't process.
Here's a link to the cat whole grinds:
animalfoods.ie/raw-dog-cat-food/alaska-natural-cat/

Are these okay to feed on their own, or should I supplement with meat chunks and bone in meat to ensure they're not getting too much organ ?

I could also try asking my local butcher to make whole grinds/daily meals pre packaged for me - but I'd need someone to tell me exactly what i'd need for their base daily meals (how much of each organ Is mostly what I'm concerned about) so that they're getting proper nutrition.
I can of course supplement those meals with some weekly fish, mussels etc for the vitamins that they need less frequently.

TL;DR
Are these okay to feed on their own or do I need to supplement ?
animalfoods.ie/raw-dog-cat-food/alaska-natural-cat/
And
What exactly do I need to ask for in a custom whole grind for daily meals ?

[infernalancestry]

The same site also has other complete grinds, ranging from 35% organ to 15% organ - they have all the nutrient compositions listed on the listings but I'm not a nutritionist nor an experienced ferret owner so I'm not exactly well versed in understanding this stuff

[Corvidophile]

Generally you want 10% organ (half of this should be liver), 10-15% bone, and 75-80% muscle meat and fat, of which 10% of the total diet must be heart (heart is considered a muscle meat for raw feeding purposes). So you’d tell the butcher you want a mix of 5% any secreting organ, 5% liver, 10% heart, 10-15% bone, and 65-70% muscle with fat. Does that help?

[infernalancestry]

Yeah that really really helps thank you so much !!