Tape a yardstick to the end of your tiller. Sit on your coaming (or as far outboard as you feel comfortable). Use the yardstick (or whatever you can find) to push the tiller across the cockpit as if you are roll tacking. Measure from the tiller to your hand position. If you opt for an adjustable stick (I certainly would) you can use this measurement to help your decision.
I use my tiller extension ALL the time when I'm hand steering. I love to sit on the coaming using the lifeline as a backrest (please, no safety comments.. I'm always clipped in). The great visibility allows me to also see my jib telltales, instruments, mainsail without craning my surgically repaired neck.
Back in my Nacra sailing days I had a long aluminum multi-section unit, but then I noticed a lot of guys were using very long, one piece extensions... most were very light fiberglass rod... so I went that direction also and it really helped... for one they were 1/3 the weight of the sectional aluminum versions. But the best thing was you could tuck it under your arm when sitting or hiking out... freeing up both hands to handle the mainsheet AND traveler, while the crew deals with jib sheet, cunningham, mast rotator, barber hauler (on my boat), the spinnaker gear (Not my boat) and the all important huge dagger boards.
Your usage will certainly be less hectic, but a tiller extension will definitely provide you and crew an enhanced sailing experience.
The Forespar device I use on my Cat 27 has a knob handle and adjusts from about 24" to 36".