Yes do it, it worked so well for us.
I wasn’t worried about what the species were, as long as they fitted the criteria.

For tomatoes, the most important was diversity, low growing, and easy to terminate. The flowers that worked well for us this year were yellow Trefoil, Reseda Ordata, dwarf Tagetes, Allysum, Ageratum, and dwarf Calendula. I think Limnanthes Bellis and Statice could also work well. In many ways, I would prefer plants that didn’t flower as much so they are putting down more root exudates. The problem is cover crop plants have all been developed for large broadacre crops.

We relay planted the tomatoes into an existing lettuce crop. We had left gaps for the tomatoes. At the time of planting, I drilled a row of flowers on the outer edges of the bed, close to the lettuce. We had a very cold spring so germination was pretty rubbish.

Having failed with this last year I was determined not to have bare soil, so we’d sown flowers into modules in case they were needed. These were planted into the bed as soon as we cropped the lettuce (about three weeks after tomatoes were planted).

We loved working amongst such beauty, so good for the soul, and the tunnel was cooler in the mid-day sun.

The tomatoes loved their companions, we had no splitting, tasty good quality fruit that lasted well.

The soil loved their green blanket. Fewer weeds, no soil cracking which always happened before, even when we had a mulch. Soil is often compact after tomatoes, not this year.

Some beds we strimmed the flowers towards the end of season and relay planted around the tomatoes with a cash crop.

Other beds we terminated the whole bed. We mowed everything in situ, raked the mowing’s into pathways, and hoed. We then sowed or planted our winter salad crops and tossed the mowing’s back onto the bed.

There has been no fertilizer or compost needed, and the winter salad crops growing in these beds now are the healthiest we’ve grown. We’ve had some pretty weird weather for the time of year so disease and aphids could so easily be a problem.

The yellow trefoil I mentioned was sown one row down the middle of the pathways. This also works great. Reduces compaction and easy to cut back or hoe either side of trefoil if needed. Still growing, we will terminate in the spring and start again.

Cucumbers are much easier as not worried about the height.