Can I just lop off Schefflera actinophylla/pueckleri tops?

I've had fun developing my poolside tropical scheme here in SoCal's San Gabriel Valley. The anchors for my tropical look has been my big and wild scheffleras. Looking to expand my tropical section, I bought some more scheffleras thinking I would get the same results. Turns out, I have 2 different kinds (species? cultivars?) and the newer ones are growing quite differently than my successful ones.

Not sure if my healthy ones are the octopus plant variety (Queensland umbrella tree/s. actinophylla, I think). I'm wondering if my tall and shriveled new ones are s. pueckleri or maybe the Amate variant of s. actinophylla. But I will ask that question in the Plant ID section later.

My new tall plants have grown a few feet straight up from their height at the time of purchase. But all the new growth is compact and scrunched up. You can see the distinct line between the healthy height (up to about 6') and then all the compacted growths above that in the photos (below). They get direct sun and some pretty high temps during the summer so I'm thinking that the shriveled new growth is a result of the heat.

This variety of the plant has had virtually zero horizontal growth, which is disappointing. I've read that scheffleras welcome hard pruning, so I'm thinking of just lopping off the top, unhealthy parts with the hopes that action may encourage horizontal broadening. I had hoped they would blend together in this landscaping, so I'm hoping that my pruning efforts may widen the tall guys so all blends together better visually.

Is this a good plan?

Thanks.

Looks like they reverted back to a different part of the gene or whatever. Think I would cut them off at that point and see if you could root them and get a new plant and the same time maybe it would help the lower part of the plant become an attractive type you thought you were getting..

Just a thought. I have never had one so don't know anything about them.

Cuttings root quite easily. Take cuttings from the ones you like and start new plants. Ditch the ones you don't like. They will never be anything but what they are.

DaisyPlantLady,
Where do I get the cuttings from. Woody branch pruning or from snapped off soft leafy branch?

Semi-ripe wood - that's growth from this year that has started to harden. This is the perfect time of year for this project.

Use cuttings that are 4 - 6 inches long cut below a leaf node at the bottom and above a leaf node at the top. Leave two leaves but cut them in half. Slice a 1 inch sliver of bark off the base of the cutting, treat with hormone rooting powder or gel.

Use a potting medium that drains quickly (equal parts fine bark and milled peat or rock wool). Use pots that are about 3" wide x 4" tall. Poke a hole with a pencil and insert your cutting. Firm the soil and water well. Treat the surface of the soil with a fungicide to prevent damping off. Keep them warm, the humidity high and use bottom heat. If you don't have a plant heat mat, the top of your refrigerator is perfect. Cover them with plastic bags to keep the humidity high and wait. Take the bags off every few days to check moisture. If they need water, bottom water.

They should root within a couple months. You will know when they are rooting because the tops will start to grow also. Don't repot until next spring.

Daisy