Mainlining 8 or 16 head buds? 6 Plants in 2 Gallon fabric pot's in a 2x4 tent.

16 will give you more overall yield. While 8 will be bigger buds but less yield.

go for 4 primary colas per plant and you won't overcrowd while wasting less time on needless vegetative growth. the yield will be the same. 24 colas is 3 per sq ft, and that's plenty to maximize yield. if in soil, i don't think a 2-gal pot size would work well for 16 colas even if there was room. If in soilless, that's a different equation and is possible - depending on size of plant may need to water 2x/day by mid flower. once you get beyond 2.5-3 colas per sq ft, it's just masturbation. It can make a grower feel good, but not gonna make a difference in production. Just gonna spread out the bud mass and get a high quantity of smaller buds. DLI and area (m^2 or sq ft doesn't matter) = production (mostly). In ambient co2 conditions with complimentery amount of DLI you can do 50-60g/sq ft with good yielders and possibly more if you clone a monster to fill the tent, but cramming an excessive number of colas in will not increase grams per sq ft beyond that limit, all other factors the same.

Prob don’t have room for 16 but you can try

I dunno, depends on how long you veg. Last time I ran a mainline I did 6 plants in 5 gals in a 4x4 and 8 tops each felt crowded, but I had also ran like an 8 week veg. Seems like a lot for such a small space so I'd run them pretty fast.