It helps to learn to install bolts by "feel". Most mechanics would have no trouble threading just about any bolt blindfolded. For auto mechanics this is practically a job requirement.

On the RD, you want to use either a T-handle allen key or, if you're trying to save packing space, a traditional L-shaped key works too. Don't use a multi-tool -- they're intended for emergency use, not routine (dis)assembly. Put the long end of the key into the bolt head and hold the key close to the bolt head between your thumb and forefinger. Do not touch the T-handle or past the "L". Use a "rubbing your finger" motion to rotate the key just as you would if you could get your fingers directly on the bolt. Rotate the bolt a complete turn and if you don't feel it catch then adjust the angle slightly and repeat. You'll know by feel when it starts threading in correctly and you should be able to get two or three full turns into the threads before you need more torque than just your fingertips.

For really stubborn bolts, the "rotate backward trick" can be pretty helpful. You apply a little "downward" pressure on the bolt and as it rotates backward past the thread engagement point you'll feel it drop down a fraction of an inch. Stop immediately and rotate forward and the threads should engage.