This is my progression system that I use every time with good results.
Start off by breaking the 105 chips into 3 stacks of 35 chips.
The rules are as follows:
1. Play through stack 1, placing chips on any straight up number. Use only 1 chip per number and place on any amount of numbers you want (less than 35)
2. When you run out of the first stack, move to the second stack. Play the same way, except that you will place 2 chips on the numbers instead of 1. Second stack = 2 chips per number.
3. When the second stack runs out, move to the third stack. Place 3 chips per number, on any amount of numbers you want. Stack 3 = 3 chips per number.
You can have more stacks of 35 chips if you want. For example, 8 stacks would require a bankroll of $280. Every time you move to a new stack after losing, you have to increase the bet per number by 1.
At any time you win. Simply reset the stacks (35 units a stack) and repeat the process, starting out at stack 1 = 1 chip per number.
This is a very fun, and easy to calculate method. I usually bet 3-4 numbers, but sometimes I get a hunch and bet more numbers.
Your win will be anywhere from breaking even if you win on the last chip in the stack, to gaining a profit of 35 for winning on the first 1 chip in any stack.
I love this system, because it is so easy to calculate. The beauty is that you can change the amount of numbers that you play on any spin and still win. (I usually play 3-5 numbers a spin)
And, if you are feeling lucky, you can skip stack going from say the first stack betting 1 chip per number to the stack 3 betting 3 chips per number to make a bigger profit.
Remember to quit while you are up!