reducing tier how much land to sell/abandon?

[Storyof Oh]

I currently have 1/4 Sim on 2 mainland locations and want to try and reduce to 1/8th. As i have set the land to group owned im confused as to the premium i get/lose

I currently have 3344 on mature mainland single prim allowance

also 15232 on adult mainland double prim allowance.

If i get rid of all the mature how much can i keep or how much must i sell if easier to get down to 1/8 sim on adult?

my current land holdings also tell me i have 10 sqm available. I have no land contributions from anyone else nor rent any tier.

Many thanks can never figure how Lindens managed to make this so complicated.

[LittleMe Jewell]

If I'm understanding your question and still remember the calcs/rules:  You want to pay for 1/8th sim, which is 8192 sqm.  You get to add in the 512 sqm that you get for being premium plus the 10% bonus that the group gets - so you need to get your total holdings down to 9574 sqm.  Your tier donation to the group would be 8704 (8192 + 512) and the group bonus covers the other 870 sqm.

[Storyof Oh]

Many thanks it was the 10% bonus amount i had forgotten xxxx