I used to plant in hills 3 to 5 seeds but that took a long time. With the planter the seeds are dropped in rows, maybe 2' apart +/-?
The way we do it now (you gotta love pumkins for all this work...) is to start them in those little expandable peat cups. The reason we do this is to start seeds in the 115 day time frame we need to have them ready by end of September. Our field does not drain well (working on that problem) and I'm always rushing to get the field plowed, disked, etc. in time; all of this coincides with the timing of our first hay cutting as well. This is a part-time job for us so it's hard to get things done on time. Anyway, starting them in these peat things gives us a week or two extra to let the field drain, warm up, prepared, etc. Then we string a line for the row and plant the seedlings along it. We space seeds and rows based on the info Harris seeds supplies. We grow:
Magic Lantern, 2' apart in 8' spaced rows
Aladdin, 3' apart in 10' spaced rows
Howden Biggie, 40" apart in 12' spaced rows
Takes a good day to plant but it seems to work well this way for us. All the big producers in the area use modified corn planters. I don't think I could do that here unless I get my soil in better condition...my field would never be ready on time...