Technique is fine, but won't be suitable for y our purposes. "Sneak Thief" by Larry Becker is an excellent routine which ends up in a drawing duplication, as is 4th dimentional Telepathy (Cassidy/Annemman)
"Back to the Drawing Boards" by Michael Weber is worth you consideration. He has it published in lecture note format. Plays big by involving four audience members each drawing their individual drawings.
There are numerous Drawing Dup bits that you can pay a small fortune on and many more that can be done for next to nothing. My first suggestion is to learn Bob Cassidy's handling of 4th Dimensional Telepathy it is one of the cleanest, most practical bits of billet work I think I've ever seen (and used... it's a constant in all of my shows and has been for over a decade). There is likewise the Orville Meyer dodge in which you use a center-tear...
(Either before the show or in actual show time) you hand the spec a billet, have them draw a simple picture... now, as you move into things pause, pointing at the dinky billet... "I don't think anyone is going to see what you drew"... take the slip, tear it up and let the pieces flutter about (you know what to do)... hand your helper a larger drawing pad and have them re-do their sketch in a larger view so everyone can see it... voila! you can now blow everyone's mind... [See Corinda re: CT]
I've pushed the envelope here when it comes to exposure so I'll not share anything else, but just think a bit, there are dozens of ways to steal an image either live or as part of pre-show. If however, you wish to go with a Clip Board, I'd suggest looking into John Rigg's Brown Hornet or any of his other pieces.
BTW... You can use TECHNIQUE provided you stress "simple" design and you are proficient in the method... people did this for decades by employing the original technique found in Corinda... imagine that.