sorry I didn't read all the answers but...here is a tip I posted a couple of years ago...or seems like it...
Stop thinking of your press as a press and think of it as a shaper...
for lentils...pick up the top and let the hot glass settle into the space...
Lentils are the hardest, it is nice that now they have presses with straight sides at the bead hole for lentils...I believe it was my suggestion...
anyway...I use my lentil press as a marver at times...just the top...
for lentils... get the right size gather and then while hot enough for the glass to move but not soupy.... lay it in the top of the press as you hold hit upside down...
I am sure you will find that lentils will shape nicely if you do that...it allows them to spread gently. Once you have the glass evenly distributed with this method ...the press is a cinch...
This is why presses that make coins or squares etc...are so easy to press...they have straight sides and the hot glass hits the sides and works its way back to fill the space...
With the lentil press if you don't have exactly the right amount of glass...it will be wonky.
After a while of doing this you won't have any more problems...
I usezooziispresses...and no don't pick up the top and hold it over your lap while settling the glass. I was lentil handicapped until I started doing this.
and really if I am going to marver a round bead...why a flat marver...I marver my regular donut beads in the top of the lentil press...you will get very good at knowing exactly how cool you need it...
just my 2.5 cents worth... a nickel isn't worth what it used to
(I haven't made beads in a year....I think I am getting read to start again!)