Short answer, you'll be fine no matter what.
Staging, especially direct staging, gives you a lot of leeway. The motors should be taped together and under compression for the entire flight so they're unlikely to fall apart, but the ignition of the motor produces so much pressure they're unlikely not to separate on a nominal flight. My custom Boosted Arcas stager has a rather tight coupler, but a D12 lighting up has enough pop to separate the stages, pressurize the entire foot long BT-50 stuffer, and kick said stuffer with a parachute wrapped around it out the back of the booster.
Many LPR stagers don't even bother with a coupler- they just use the motor itself. The coupler is just added insurance.
Another note, don't overlap the Scotch tape on itself. The one flight I did this I got a nice little 90 degree turn at staging.... That may not be the problem, but I've had 100% success ever since.