Remember master Lin's Good,Better,best philosophy. If you are practicing daily that is great! Consistency is important. I still remember 5 years ago when I first started asking Master Nance if I do my active exercise in the morning and mediate in the afternoon would it still help. His answer was "thinking about it helps!". The message is that Spring Forest is a way of thinking,behaving,viewing the universe as much as anything.
Having said that, the right amount of time is whatever time you have. If you can do it all at once, start with an Active Exercise and follow with Small Universe. Feel free to mix in other Self Concentration and Butterfly Mediation too.. If you need to split the time up that is OK too. During the day, take 5 minutes (or whatever you can) and run through part of Breathing of the Universe...it all adds up. The "Best" when starting out is to spend 2 to 1 Active to Mediation, so adding small Activate Exercise "time outs" during the day is helpful.