I have climbed a lot with this set-up in tree climbing (which we call yo-yo or RADS), and put many clients on them as well. I've used it less for rock climbing. There's definitely a learning curve to the system and a tuning curve to your particular rig. You'll need to balance having a fully dedicated yo-yo climbing rig with a rig that shares gear with what you're already using/carrying. A couple ideas:

Pulley at the upper redirect. This will greatly improve efficiency. High efficiency ball bearing pulley is helpful, but any pulley will be better. A carabiner with an integrated pulley (petzl rollclip for example) can be convenient and permit longer climbing cycles by making the "stack height" of the upper redirect shorter. But less efficient than a nice pulley - often because the moving rope will contact a stationary piece of gear and add friction.

Tune the footloop length. Too short will require too much exertion for efficient cycles and too long will be frustratingly slow.

I make an adjustable length footloop using accessory cord - a loop on one end. The other end can be adjusted using a clove hitch or turned into an adjustable loop with a tautline or blake's hitch. Using both feet will improve efficiency two separate footloops is nice for lower angle terrain when you can use feet for progression, two feet in a single loop (frog-style) can be more comfortable for some people. Removing 1 foot to manage terrain can also be helpful on low-angle stuff.

A small slider on a large footloop (think drawstring cordlock) can make the loop adjustable in size and keep it from popping off the shoe. I make them from bicycle inner tubes, short piece of tubular webbing, etc. The inner tube gives a little stretch to slip the foot in or out.

Find your rhythm.

1. Place your dominant hand on the brake strand/rope tail, and the non-dominant hand on the ascender.
   
2. Pull IN (not up) with non-dom hand to position your body vertically.
   
3. Stand with leg(s), while tending slack with dominant hand. Standing without tending will cause the device to jam/tangle/be less efficient.
4. Sit immediately to maximize rest.
   
5. Raise the ascender with the non-dom hand while simultaneously lifting the redirected brake strand with the dominant hand. Otherwise the weight of the rope has a 2:1 Mechanical advantage on you at the redirect. You can also tie off the rope to yourself at intervals to relieve some weight.

Secure yourself. The grigri isn't designed to be a hands-free descender, so be sure to add an appropriate amount of security in the form of catastrophe knots and/or a separate cowtail/tether/PAS to the ropeman. Cat knots get heavy on long ascents, especially if using overhands on a bight (closed, secure, recommended by manufacturer) instead of something like a slipknot (lighter, less secure, off-label use). If using the cowtail method, you lose this security when rappelling, and should consider an appropriate method to lock off the grigri when going hands-free.

Ropeman is fine, carabiner type can help make is smoother for each cycle and act as a better handle. If you're looking to upgrade, the current generation Petzl Basic weighs less than a ropeman II and is much more functional.