Russian and greek tortoises are pretty small, but they do need some sunlight. In fact, all turtles and tortoises need sunlight to turn calcium into d3.
If you can give them 2-3 hours of sunlight outdoors each day, except in the harsh cold or wet days, you might be able to get away with it.
Russian tortoises are a challenge, because they're usually not CB, and they come in with parasites and nasty respirtory infections sometimes. Once you've gotten through the first year, with the vet bills and acclimation and all, you have to take all precautions not to let them get resp. infections, etc.
The other challenge might be to try to get a good diet for the russians. I've found a small piece of food information on a care sheet below:
"Feeding
Your new tortoise will most likely eat anything, atleast anything that's bright green, yellow, or white, or red. So, if you are walking your tortoise (yes, some people do it) out in your yard, or if you're putting it in an outdoor enclosure, you will need to make sure there are no toxic weeds or other plants in the enclosure.
The perfect diet, from what I've gathered, is a low fat/calorie, low-sugar, low protein (4% or less), high calcium to phospherus ratio (2:1, 3:1, etc), high fibre diet.
Looking in nutrient charts from plants, edible flowers/weeds, and dry tortoise foods (t-rex, mazuri, etc), there's no way to provide the tortoise with a 4% or lower protein diet. Dry foods have appx 15% to 18% protein, some over 25% protein.
In reality, the total protein in the diet is going to be around 14%-18%. There are a few veggies, flowers, and weeds that may be lower, but for the overall health of the tortoise, it needs a larger variety to get the total calcium, phosphurus, and fiber it needs to survive, without over-doing it on the fat, sugar, and protein.
The tortoise's favorite foods are flowers. Dandelion blossoms are a favorite and have been known to get even the pickiest of eaters to eat. Pansies and petunias are also taken.
Mulberry leaves, grape leaves, and hibiscus leaves may also be offered. Different types of non-toxic grasses and hays may be offered as roughage. It was recently brought to my attention that they'll also eat maple tree leaves, but I personally don't know what types of nutrients, or risks, are in them.
Dry tortoise foods claim to be perfectly formulated for herbivorious tortoises. While this is probably the case in most of those tortoises, the foods weren't made with Russian tortoises in mind. They include fruits and sugars that just aren't advised on their diet, as well as a higher protein
than the, "perfect" diet.
After talking with a few of the fellow Russian tortoise keepers, I've come to the conclusion that dry tortoise foods should only be used once a week, or less. That way, the bad ingredients wouldn't really be in a sufficient enough ammount to hurt the tortoise, but yet still adds the variety they
need, as well as calcium and D3 in some cases."
One other thing about russians is that they should be hibernated atleast every other year, due to possible health problems.
Keeping russian tortoises isn't cheap, by money or responsability standards, but if you can handle it, it could be very rewarding. Russian tortoises aren't for everyone. I hope this helps.