First time hydro need help sexing and input!

First time growing. I have started 4 different strains from seeds and now the plants are around 7-8 weeks i would like some help sexing! The plants are on 18/6 with light periods with 4 24' T-5 6500 0r 6700 spectrum bulbs the plants are in a 18gallon tote that is pump fed from a 5gallon res that is aerated with a small fan blowing above the plants.and will be moved into flowering room with two 600w HPS and each plant in a 18g tote that is fed from a 100g drum with several 2/gph misters on 1/2 lines in each tote that will run off a 360gph pump. the room set up is bloom side 12wideX16 and veg is 8wideX16 dry-walled and sealed. that and any input on color and size of leafs, stem size, length ect. Any advice i would appropriate greatly. Sexing is first picture and rest are grow-room

Too early to tell.

you will work less, your ph will stay more consistant, and your plants will be happier with a larger res.

Ok upgraded my res to 20Gallons thanks superstoner1 made a big difference plants have many less burn spots. Have a few new pictures of nodes for sexing now its been over 2 months and im startng to wonder what would make the plants not show any sex still. all four are different strains only one is femanized and the feminized seed is near half the size of the plant im taking pictures of. because of the size in general i wanna just keep the largest one even if it is a male to breed to my fem seed plant. the stem is huge and it has growen on ave 13-15 inchs foot per month. that a decent rate? bottem stems for the lower part of the plant are almost as tall as the top of plant itself. sounds like a male?
Should i just make clones of the fem plant and start flowering it? and save this plant for when i want seeds?

Going to make some clones and flower them now unless anyone else says otherwise.

truely, do you want to mess with making seeds? stay with cloning. i get rid of any male, asap. i dont want the chance of a seed.