Forearm Map Holder/Arm Caddy

I partake in a number of Adventure Races (personally I'm very amateur!) and the final event of the year is a short race around Brisbane (Australia) city at night. 

We need to carry a piece of paper with instructions and possible answers to mark so I thought there must be a better solution than having to retrieve a crumpled piece of paper out my pocket multiple times in the race.

Twice I even managed to lose the paper which was terrible.

My current solution is a self made map holder which can strap onto my forearm and has holes cut out of the front to mark the answers.

Materials required - thin clear plastic sheet and a few velcro straps. I purchased these items at a sewing store for hardly anything and have plenty spare.

For the upcoming event we were using A5 pieces of paper so I measured the plastic to suit.

Next step was to attach the velcro. I thought to do this before attaching the sides of the sleeve in case I needed to staple or sew the velcro to the plastic.

For ease I simply stapled the sides together. Other options include super glue or using a sewing machine with an appropriate needle.

Looking good so far.

The last step was to cut out holes to mark up the answer sheet. I created a lattice framework to provide some strength and keep the map inside the cover. 

And it's done. Not overly pretty but will be effective. Very cheap to make (+-$3) and about 15 min of effort.

The only modification I can think of is to have a strap running through my palm to stop the map case from rotating around my forearm. 

I've tried using the map cover for an hour and it doesn't seem to move much so won't make this modification yet.