We don't train anymore at age 28 except stam and ft's. My understanding of the current state is that we need to first establish a core of players first. Don't get me wrong, there are some great players out there individually but a core will generate more success long term and we can remain more competitive in the long run. Its like a flat tire that we keep patching up, instead of buying a new set of wheels. I hope you and the other candidates are up for it.
Well, it depends on cap. I've trained a NT player with 30, but usually is as you has told.
What is your idea (tsp wise) of Senior players in all positions?
Ufff, this question has many different possible answers depending on multiple cirumstances, for example combination of different players skills, tactics, ...
I prefer to speak about minimun skill levels in some position: for example, in PG and SG you must have an OD in 19-20. Can a PG/SG with OD 18 play in NT? Well, it depends on other skills, skills of his team-mates, the other team, tactics... but it's desirable an higher level.
(I think that your community must open a federation to speak about your players... Now many managers can know about your team. It's true that many top players are very similar but...)
I don't know if I have answered you. If not, let me to know.