The average rate a player gains sp
is his rate. There is no difference to that anywhere
afaik. If your player averages 3% per 1 condition over 30 competitive matches and 30 training sessions then he'll get the same average over a long period in friendlies.
The difference between friendlies and competitive matches is the condition consumed - friendlies consume on average less condition.
I've not seen any evidence to suggest there is a ratings multiplier on gain. I've never really looked to see if there is a difficulty multiplier for friendlies either.
Additionally, I've not seen the level of starting condition affect sp gain. If a player has enough condition to complete the training/match he'll get his expected gain (subject to variation)................IMO.