A lot of this is knowing your options in terms of followups to perfect shield. This is almost more reactive than proactive.
Honestly, I'm not good enough at all of this to pull it off consistently. I'm getting proficient at perfect shield to rest, which mostly is remembering the moves with enough lag, their timing, and the spacing required. SDI into rest is a little tougher, I need a good deal of practice to consistently rest Diddy out of his forward smash. SDI out of a move into rest is definitely doable.
Perfect rest is really tough. I can perfect rest snake out of his mortar slide pretty well as well as any compatible smashes if they are charged. I found out about perfect rest by using it in friendlies (it was a 2v2) on Kirby's forward smash (seriously, if someone charges a smash... the smash would have killed me, I thought if I exploited rests invincibility frames there might be a chance my partner would QAC me out of lag).
Whether this is truly reliable or not is up in the air (much like Jiggs). I believe that at least a sizable portion of this will be usable, especially resting in between hits. Its still very new... "crosses fingers"
I will not have video up till Christmas unless I get really lucky. Sorry. Aside from the lack of equipment, I don't have the critical mass of footage yet.