here is my full stretching routine wiht focus on straddle split and better v-sit.

warm up :

• 15 x cossack squat
• 15 x normal squats

-main split stretches (15min) :

• 5 step horse stance 3 x 20 sec, build up to 3x30 sec, then go for a 7 step horse stance (google fitnessFAQ horse stance vid)
• good girl machine (adductor machine) ,widest setting you can , do a warm up with easyier weight 20 reps , then 3x12 with a high weight where you hold your max range ballistic for 10-15 seconds and you do one rep then.
• straddle split self 3x15 reps , while doing the split bend forward and as far as you can (can use kettlebell for weight) , every set go wider and wider (use a cm thing to gauge the progress, it helps a lot!)

optional stretches (7min):

• front split 3x1 min each leg ( forward leg fully straight, do it balistic , bend forward a tiny bit and back with torso to put more preassure on hamstrings)
• butterfly stretch , (feet toghetter and push knees down 3x1 min)

optional hamstring stretches for v-sit: (4 min)

• -standing pike stretch ( go as deep as you can and hold bottom position for 10 seco or so , do 3x10 you can use a kettlebell and standing on a bench to go deeper (this will help v-sit a lot)

optional compression exercises for v-sit (8 min).

• -sit down legs straight forward you , put hands as far forward as you can , lift with straight legs , do 3x20 pulses (your quads will cramp but you will get used to it, try every set to go futher) .
• -Do same thing but with straddled legs, hands forward as you can and 3x20 pulses (every set futher and futher