Crepe Myrtle Pruning

I purchased a property last year that includes some lovely crepe myrtles. I've included pictures of a representative group of them. I have a few questions:

I would like to prune several of the trunks growing up from the ground - possibly down to 3 or 5 trunks per plant. Is there any drawback to doing this now, as the plants have started putting out new stems and leaves? Or should I wait until next season? Should I do this all at once, or only a few trunks a season over several years?

These pictures show the plants as recently pruned by my landscaping guy. They look good to me. Does anyone have advice on how they are pruned?

For scale, these are about 9 or 10 feet tall.

Thank you!

First of all Ryan, there are big differences between the trunk and side branches, I think what your describing are side branches.
The Crepe Myrtles are Multi branching SHRUBS, the pictures shown are a true representation of what the Shrubs do look like wherever they grow.

Sometimes it becomes necessary to remove/ prune some inner branches that are preventing air circulating the shrub and it becomes leafless in the middle, or outer branches are needing removed because they habe grown right across another branch, this allows these branches to rub together and in turn lets diseases enter the rub wound. you would remove one of the offending branches.

Lastly, it is never good to prune shrubs when the sap has started to rise as it makes the cut's bleed attracting insects to come and either feed off the wound or spread diseases.
If the shrubs have only recently been planted, all I would do is give them a multi purpose feed, this normally comes as granules so after you spread the INSTRUCTED amount, give it a light fork into the top soil, IF you get extreme hot weather, it might also be a good idea to get a load of leaf mould or other type of ground cover / mulch, add this after you have absolutely soaked the ground, the mulch helps retain moisture and keeps the soil cooler around the root areas.
Hope this helps you out, I think you will have a lovely focal poind with a nice clump or the Myrtles and tree in the backdrop.
Leave well alone I say for a couple of years before you think about pruning UNLESS it is really causing concern, just enjoy, have fun with your new garden and relax.
Kindest Regards.
WeeNel.

Yes, it is OK to remove some of the many trunks, but not all at once. Perhaps one per year. The ones remaining will not spread out any more, though. To maintain a nice multi-trunk effect I would select well spaced, outward growing ones to keep. Remove inward or crossing ones.

Ugly pruning job in my opinion.

There is room above for them to grow larger.

I would thin the new growth to just a couple of well placed new branches, growing outward from the center in hopes of training it up and out more.

Dormant season is best for the major pruning, but I would start thinning that witches broom right away, pinching out 75% of the mess.