Was going to jump in with all sorts of practical advice but then I saw that you live in a hot climate (Southwest?) so am not sure how to grow pumpkins there.
I normally plant a medium size pumpkin (Connecticut fField, for example) so you can get one or 2 carvable pumpkins per plant. Regarding how many seeds to plant, an old New England farmers saying is to plant 4 times as many as you need, as some will not germinate, some will get eaten or destroyed. Around here, we plant toward the end of May as it is really not warm enough til then and harvest in September. Also, the plants need lots of room. The vines can go 15 or 20 feet
I think your conditions are so differnt that what I have, you might want to check local sources
when the frost is on the pumpkin....