A tool for MQ designing

I'm ready to start machine quilting my blue/purple/turquoise kaleidoscope, partially finished.  Long sweepy watery lines seemed to be called for, as it is supposed to appear ocean-y, or underwater fronds, not easy on a DSM due to limited hand space.  I needed to practice ... something ... so I bought a 12 inch piece of plexiglass, covered the edges with masking tape, indicated which side was "UP" on the tape, and put the detailing quarter inch tape on the back as quidelines, whethee they were used or not.  Then I placed the plexiglass over the quilt block, and used a dry erase pen to play with designs, and came up with below.  The masking tape on the edges keeps the plexiglass from scratching the quilt, and also serves as a STOP if I get wild with the dry-erase pen! 

My tape does not exactly match up with the wedges but since I usually MQ free-form designs, it's working for me.  My note says "Draw this Side".   

I MQ one block at a time - have not figured a way to continue the design to the next block without breaking thread.  My thread is variegated blues - kinda goes with the many fabrics in the kaleidoscopes.  It's a start!