How do you decide which grasses to use?
Usually decided by super, architect and owner based on expected clientele, # of rounds, competitors in the area and surface desired. Once a type (bent, blue, fescue etc.) is chosen. Hopefully they let the super pick the varieties used. There are so many more choices now than there were 10-20 years ago. If you are expecting less play (private club) you will want less aggressive varieties because more aggressive means more thatch. More play means you need faster recovery.
If you are going for firm and fast you want more drought tolerant and hardy varieties. If you are going for the Augusta look you will lean towards the varities with the best color ratings. Disease resistance is also a big criteria for everyone. In Northern Michigan, dollar spot and snow mold are our major concerns. The farther south you go the more diseases you have to contend with.
In the US we have the National Turfgrass Evaluation trials. Seed companies put their varieties in at trial plots across the country and they are evaluated in dozens of categories every year. If you are choosing grasses you look at the results from sites that are similar to yours.
How long does it take to get a playable surface? How long till some sort of reasonable maturity?
In the US very few courses (except Old McDonald) have the luxury of slow extended grow-ins. Generally most developers want it open within 1 year of seeding. It generally takes 3-5 years for them to "mature".
Are the maintenance procedures similar between grow in and maintaining grass? i.e. how often you water, mow, etc?
No. After seeding you need to keep the surface damp to germinate the grass asap, so you water lightly every hour or two all day long. The faster you get germination the less susceptible you are to washouts from rain events. As the grass germinates and fills in you water deeper and less often to stretch the roots downward.
You also fertilize lighter and more often early and stretch the intervals as the grass fills in.
How difficult would it be to grow in a course without irrigation?
Seed timing would be the most important thing here. You have to depend on Mother Nature for water so you would want to seed just before the rainy season in your area. There might be more washouts to fix, but you won't germinate anything if it doesn't rain.
How did the old guys do it?
I don't know, but I would guess that there was enough farming knowledge from the people involved that they just applied those principles. Back then they knew that it would take longer to grow in. They didn't have the tools that we do now. I think it probably took them longer to build holes so they would seed as they completed holes, then play what was available, whether it was 3,8 or 12 holes till they were all ready.