Hey man,
I'm only 21 years old, slightly receded hair line and have been using a partial piece at the front for over 6 months now, I've posted various pic etc on here before.
Don't let anyone tell you you can't wear a piece as small as 1cm, my pieces are the exact same as you described with the triangle sides held by a line in the middle to bring you hair line forward and the angles will fill in the receding temple points.
The trick I used was advice from Paul, when he suggested ordering a stock unit and cutting the piece using my template as a guide against the lace. It's surprisingly so much easier than you think. I was a complete newbie and amateur when I managed it so I'm sure you can!
The plus side is after maybe a few weeks to a month because Im quite hard on the system Id'd cut a few new pieces, sometimes slightly different lengths depending what style I was to go for, so one stock unit has lasted me 6 months so far! Complete value!
As long as the colour matches your hair and you have plenty of hair to blend into the piece noone will ever ever know. Noone has a clue about me
Also I use tape I buy from ebay and it's mega strong, don't worry about thinking if it will fall off, I generally have a greasy, oily scalp and the tape lasts so well I play gigs with my band all the time, jump around sweating, I play sports, hit the gym. Nothing stops me
Good luck
Leondon90