I pickle and can my cucumbers and my squash. I prefer the wide mouth jars (just easier to put stuff in them). I don't have a pressure canner. I use my roaster oven. Put about an inch of water in it and put your jars in and turn it up to 450. Then I cook my brine until boiling. stuff the hot jars with goodies then pour boiling brine in. Put the lids on and hand tighten. sit the jars on the counter and cover with a towel to slowly cool. You should start hearing the lids "tink" as they cool and seal. I do pickles, squash, okra, relish and salsa verde this way.
Are you acidifying? Squash has to be acidified/pickled to safely can and Okra has to be pressure canned (unless also acidifying/pickling).
If you are just water bath canning, you should just use a large pot and do it on your stove top (with a wire mesh tray so the cans don't touch the bottom of the pot). Pouring in boiling brine and putting the lids on, even for pickling, isn't the safest way to can whether the lids seal or not.