Pretty good overview... ships actually have become a bit more expensive since VB6 version. I think the cost for paying total ship cost there was 20 years, but I could be wrong though.
It can be quite valuable to keep your maintenance life value to around 2-3 times the ships deployment time. Every time you retire the ship to port for resting the crew you also overhaul the ship. Also, the more engineering sections you have you also have a higher chance that you don't get any failures. If the ship have maintenance life of three times the deployment time there is a very good chance you get zero failures.
You also should consider not using maintenance storage on warships. You are way better of adding more maintenance facilities to reduce the chance of failure instead. Make sure to have supply ships close at hand instead.
I usually keep my maintenance life of ships in the range of 1.5-2.5 years for most regular warships that typically have between 6-12 month of deployment time. It is a fairly good trade off between space and economy in the long run. Engineering spaces will generally keep maintenance costs down. You also should consider and engineering station on larger ships as that will keep maintenance failure even further down, especially with a good officer in charge.
I like maint bays on warships, to a certain limited extent. I don't like relying on my (slower, undefended) supply ships keeping pace unless I have to, and spending 50 tons to get my MSP up is often a good investment. Doubly so if the ship needs to refill MSP for parasites, or if it has beams that can break in combat. Maint storage is often a better way to keep your beams firing than engineering spaces are, because your supply ships should really not be entering beam range, and the warships can't easily pull back to refill on MSP.
Maintenance bays do have some uses but overall they are not needed all that much. Engineering sections will both reduce the need for MSP and increase the MSP at the same time.
If you build a dedicated beam ship you "might" need some extra MSP, but even then it should be rare to run out of MSP in most cases. I think it mostly is for planetary bombardment purposes that you will run out of MSP that way. If the beam ship has a health overall maintenance life cycle it is less likely to drain its MSP on their way to the fight and have more MSP from the Engineering sections too.
You also can have relatively fast supply ships too, but I never really had much problem with my supply train anyway in Aurora when I needed them.