How tight are the limb bolts?
To tight and the limbs can be hard to install.
Suggest no tighter than 2 turns from being bottomed out.
Also if the slot that goes around the limb bolt is tight, just rub some wax on it and they slip in easier.
The clear pads don't need to be removed.
They are there for vibration/sound.
Try to slip the limb over the bolt without using the dovetail to see if this is where the problem is.
If it goes in easy then the issue will be the limb bolt is to tight in the riser, so back it out, or the ILF dovetail is drawn up into the limb to far. Did you tighten the little screw??
If it is drawn into the limb to far loosen the small screw 1 turn, and tap it down flush to the limb. Try to install it again, and repeat as necessary. When the ilmb installs easily remove the little screw, and put some thread locker on it.
Often people see a screw and instantly tighten it. These are only to be snug, and sealed with removable loctite. If you make them tight you draw the dovetail into the limb and it makes it hard or impossible to put limbs on.
Pete