In approximately one to two weeks time, dealers on a different coast of your home city will only be comfortable dealing a quantity of units up to an amount based on the reputation of the uppers' units. (CL's units + RHM's units + LHM's)/3

Examples: 

NY Crew:
CL 65 units / RHM 45 units / LHM 14 Units (65+45+14 = 124 / 3 = 41 units)
Same Coast for NY member: No purchase cap in NY and PH for any member/upper
Other Coasts for NY Member: 41 Units purchasable in LA/LV/DT/CH

LA Crew:
CL 40 units / RHM 65 units / LHM 8 Units (40+65+8 = 113 / 3 = 38 units)
Same Coast for LA member: No purchase cap in LA and LV for any member/upper
Other Coasts for LA Member: 38 Units purchasable in DT/CH/NY/PH for any member/upper

DT Crew:
CL 45 units / RHM 45 units / LHM 45 Units (45+45+45 = 135 / 3 = 45 units)
Same Coast for LA member: No purchase cap in LA and LV for any member/upper
Other Coasts for LA Member: 38 Units purchasable in DT/CH/NY/PH for any member/upper

EXEMPTIONS:

If a crew's HQ was purchased less than 1 week ago, the math is altered to be (CL's units + (Highest Unit Upper) / 2) OR the original formula, which ever is better.
If one of your named BGs has fought and beaten an NPC in a prize fight in that city within the past 24h.
If you have claimed a lounge hustle point, there is a chance you are exempt for X hours.
If you have claimed a lounge free credit, there is a chance you are exempt for X hours.
If 2 of the 3 uppers have been active on lounge in the past hour, you are exempt for up to an hour.
 

To make the math/exemptions easier, it will display the current math/status on crew info page as well as the drug page in an easy to read/understand way.

TL;DR:

Crew leaders will have to weigh the benefits for the family as a whole by selecting the right blend of hard workers/socially active/longtime friends to be the uppers.
Crew members will have to weigh the benefits of joining a family by selecting the right blend of hardworking/socially active/longtime friends that are the uppers.
You an be exempt from limits by multiple ways

How's this going to work for Drug achievements/xp gained from full load sold@Profit? Is it going to count the max as your max, or the max that you're currently able to buy due to Upper restrictions? 

It will not work you will have to rely on an exception or other methods to acquire a full pack of drugs