How do I build a maintenance resupply ship?

[Panpiper (OP)]

It turns out that my laser-armed warships burn through maintenance supplies as fast as missile-armed warships would burn through missiles. If my ships fight a battle between an equal number of the enemy, they emerge with maybe half their maintenance supplies left from full. Heaven forbid they should engage larger numbers!

I need to design a maintenance resupply ship that my fleet can retreat to, to fill up before going back into the fray. However, it is not clear to me what those ships need to do this job. Do I need to add 200 Large Maintenance Storage Bays, or will a pair of Standard Cargo Holds do? I expect a Cargo Shuttle Bay is obligatory (more than one?). Is there anything else I need to add or perhaps flag so that my ships will be able to fetch maintenance supplies off this ship?

[Kylemmie]

Maintenance Storage - Not Cargo Holds.
Yes - Does need at least one Cargo Shuttle to transfer MSP.
There is a "Supply Ship" (I think what it's called)  toggle near where you would flag a tanker or Collier. Need this on. BTW - These toggles can be flipped without needing to unlock the design. 

Don't know how big your fleets are - but 200 Large MSP storage is a lot... It will be easier if you use standard squadron or fleet org's. What I do is add up the MSP a Squadron carries into battle if fully stocked to know my max need to refill between engagements. Say it's (completely random, don't read into this) 15,000 MSP to fully stock a stock patrol squadron setup I use. I plan out a design for a supply ship that holds either 15k MSP or a clean multiple of it. That way I know I have a set minimum number of engagements that support fleet can handle. I use the full 15k MSP as my number even tho they obviously won't need full restock since they must have some to still be functioning. But I like having a reserve.