You could save time, I suppose, by using:
Infuse Mutagen
When the alchemist creates a mutagen he can infuse it with an extra bit of his own magical power. This inflicts 2 points of Intelligence damage to the alchemist and costs 1,000 gp in rare reagents, but the mutagen created persists on its own and is not rendered inert if the alchemist creates another mutagen. This allows an alchemist to create different types of mutagens and keep them handy for emergencies. This does not allow an alchemist to gain the effects of multiple mutagens—only the most recently imbibed mutagen has any effect.
Costs some coinage but it allows you to have whatever you need at hand. Can't really think of any other way except for house rules or buying some infused mutagens for 2000 gp or so.
EDIT: Although these traits may also help a bit:
Unstable Mutagen
Once per day, you can create an unstable mutagen. It is like a normal mutagen in most ways, but also gains a single benefit or hindrance due to its instability. Roll 1d6 to determine the result of the instability.
d6 Result
1 The unstable mutagen lasts for 5 minutes per alchemist level.
2 The unstable mutagen lasts for 20 minutes per alchemist level.
3 The unstable mutagen does not grant a natural armor bonus.
4 The natural armor bonus granted by the mutagen increases by 2.
5 The penalty that the mutagen applies to the corresponding mental ability score increases by 2.
6 The unstable mutagen does not apply a penalty to the corresponding mental ability score.
Enduring Mutagen
The bonuses and penalties granted by your mutagens last for 1 additional minute per alchemist level.
