If I where in your situation I would probably add five or six turbos and a half dozen scarlet hermits until getting home from vacation. If they are all alive and well when you return you can go from there.
Every tank is different so the size of the cleanup crew is going to be different also. IMO the suggestion on clean up crew size from sites that sell livestock are usually on the large size.
I would research a list of fish intended for the tank. The week you get back add the least aggressive of these fish, the following week fill out your cleanup crew a bit more, the next week your next fish etc ending with the more aggressive of your intended fish species. After that you will have a better idea on what size clean up crew the tanks going to take and fill it out from there.
Be sure to drip acclimate your hermits and snails just as you would a fish and check your SG. These inverts are going to want an SG in the 1.025 neighborhood. If you intended to add corals in the future your going to need this SG anyway. Most salt mix instructions will leave you with an SG around 1.022 so now is the time to adjust that in your tank before adding your clean up crew if this is the case.
If useing a hydrometer to check your SG double check it with another or better yet double check it with a refractometer. A good LFS shoud have one. Hydrometers are usually inacurate but consistently inacurate so if you can find someone with a refractometer you can "recalibrate" your hydrometer for a definate SG reading or just purchase your own refractometer.
Since you have quite a bit of LR in the tank and most likely quite a bit of live stuff already, even if you cant see it, if an SG adjustment is necessary raise it slowly over the course of days. You can do this with some small water changes with new water with higher SG than your tank. A rise of .001 per day should be fine. These small water changes will also serve to bring down your nitrate reading. A reading of ten is fine but with nitrates less is always better.
