Critique my uppwer/lower split
 

have been doing a regular 5 day split for about an year and a half but lately I have been reading about the upper/lower split and how it is so much better for naturals. So after doing a little research I came up with a workout but I'm not sure if it is quite right, more exactly I wanna know if it has too much volume and if the exercises selected are optimal.

NOTE: barbell/EZ curls are not an option for me since my forearms hurt when I do them no matter what grip I pick or form I use (I'm guessing I'm just not build to do standing bar curls), preacher curls work though. Also I would prefer to do exercises that don't require a spotter ( which is why I choose DB presses for chest and shoulders as opposed to BB press and military press) because I don't have a workout partner and there isn't always someone in the gym to ask to spot me.

So the workout is :

UPPER BODY:
DB bench press : 4 sets / 5-10 reps
DB flys : 2 sets / 8-12 reps
chin ups : 3 sets / 6-12 reps
T-bar rows : 3 sets / 6-12 reps
DB shoulder press : 3 sets / 5-10 reps
BB lateral raise : 2 sets / 8-12 reps
preacher curls : 2 sets / 8-12 reps
dips : 2 sets / 8-12 reps

LOWER BODY:
squat : 3 sets / 5-10 reps
leg curls : 3 sets / 8-12 reps
leg press : 3 sets / 8-12 reps
stiff leg deadlift : 3 sets / 5-10 reps
calf raises : 3 sets / 8-12 reps
ABS

As far as training frequency goes, I'm gonna do it:
Monday: UPPER
Tuesday: LOWER
Wednesday: rest/cardio
Thursday: UPPER
Friday: LOWER
Saturday: rest/cardio
Sunday: rest

HOWEVER I have a flexible schedule so I would like to know if I could do my frequency in this manner:
Day 1: upper
Day 2: lower
Day 3: rest/cardio
Day 4: repeat

So basically I don't have the 2 days of rest in the weekend, thus my workout program won't depend on the days of the week. Is this too frequent or is it optimal?