After a lot of work on all sorts of things getting my bed level, I finally went down the easy road and designed these bed level adjusters. They work with full glass and can be adjusted while the printer is running allowing fine tuning while putting down the first layer. My bed has a diameter of 240 mm but there is some movement in the wheels to allow for adjustment of bed sizes and expansion when the bed heats up.I lost about 18mm on my build height but considered it worth it to make use of the whole bed properly.

They are not designed to replace calibration. Calibrate as normal to get your bed as close as possible then any areas still out can be dialed in with these. Tighten down to around 3mm from the top of the level blocks so everything is tight and holds still. These are designed to give a small amount of adjustment + or - 2mm any more than that you need to re-look at your calibration and frame geometry.

Parts needed.

3 x 12mm long by 8mm diameter springs
3x 15mm long M3 Countersunk Screws (Normal screws will work if you don't plan to use a full-size piece of glass)
3x M3 nuts
3x M3 Nyloc Nuts
3x M3 Washers
Super Glue (To glue M3 nuts into adjusters)
Old screws (M4) from bed holders
M4 square (Already in place) or T Nuts

Assembly

Countersink your heat-bed (If using Full Glass)
Insert countersunk screws and tighten with Nyloc Nut.
Superglue M3 nut to adjuster wheel
Install level blocks so the adjuster wheel position is dead center between towers.
Sit bed on adjusters and turn adjuster wheels to secure bed.
Tighten bed until it is 3mm above the highest part of the level block.
Calibrate printer
Runs test print and adjust the level as needed.