Fitting the body?

Trousers are a staple in my wardrobe when I can get a pair that fits.  I have tried a few times to sew trousers myself but the results were worse than what I can buy.  In the nineties I made a few pairs of Today's Fit that were ok but I want more than Ok for fit.  Fast forward to today and I have been reading and seeing the success people have had with Style Arc and Burda patterns, this has persuaded me to try again.

I love the look of these pants from Style Arc - Peta's Pants.  So I started with these.  Usually I copy my patterns but decided to cut these and use without copying.  

These looked okay from the front but pulled in the inner upper leg seam if I tried to move. But all the action was in the back.  The fabric dipped down to nothing in the middle of my waist and there were lots of diagonal wrinkles.  

I decided to see what the Burda 7966 pants were like in comparison.

These pants were more comfortable in the leg but had the same problem in the back as the Style Arc pants.  I consulted this book which I find very good for helping to diagnose problems.

 And it seemed as if the problem was a protruding derriere or big butt!  So following the directions I cut into the pattern like so...

and this was the result...

This alteration helped raise the waist at the centre back but did not remove that diagonal wrinkle.  At the front it looks like too much fabric has been added but when I walk it pulls from the back.  Consulting the book again suggests that I need to add a little in the front crotch curve to allow for full inside thighs.  I made another pair and also added a little more at the centre back waist as I was unsure if I had raised it enough.

Surprisingly this has made the whole pant seem more roomy around the waist, the wrinkle at the back is still there and I think I need to reduce the back crotch extension alteration I did at the beginning as adding to both the front and back has added too much fabric I think. I am going to appeal for help in solving this and try these alteration on the Style Arc pants and see if they respond a little better as regards fit.