Pruning - what you call plucking the suckers - is strictly optional. It is not required for any reason. It is one of the enduring garden myths from eons ago when the erroneus claim was made that the "suckers", which are actually lateral fruit producing branches, supposedly "suck" energy from the plant.

It's use is tied to the type of plant (determinate or indeterminate), the plant spacing used, and the method of support used (single stakes, tripods, various types of cages, string, Florida weave, etc.) And while there is some evidence that the remaining fruit might be marginally larger, the overall production is substantially reduced. There is no proof that the remaining fruit will be stronger, sweeter, healthier, or any of the other claims made.

So do it if you wish to for some reason but only on indeterminate variety plants and as long as you understand that you are only doing it to improve the plant spacing or the support, not for the fruit that results.

You can remove them all as they develop so only a single stem results. Or you can leave 2 of them and have 3 main stems. But snip/pinch them off while they are as small as possible. Going back later and removing several large ones is very stressful for the plant.

Dave

I am also first year gardener in PNW.
In addition to what you just mentioned, summers are much cooler here and the growing season for things that need to ripen, is relatively short. I have just hear from some local, that some gardeners will even nip the end of branches and even new buds, so that the plan can concentrate on ripening the existing ones. So to ME, pruning make sense. SUCKERS are not really suckers but they use the limited resource of the root system. There is just ONE STEM that all the plants food production material channels through it.

Since the common tomato fungal diseases are airborne fungus that claim is debatable. It would more likely help prevent bacterial diseases than fungal.

One can read/hear all sorts of claims. That doesn't necessarily make them true.

I have just hear from some local, that some gardeners will even nip the end of branches and even new buds, so that the plan can concentrate on ripening the existing ones

Ripening rates are genetically controlled and there is no evidence that it is affected by top growth pruning, only by root pruning.

There is just ONE STEM that all the plants food production material channels through it.

All the secondary stems have circulatory systems too.

Pruning is always an option but it should be done for valid reasons not because of speculative claims since most are just enduring myths.

Dave