Thanks for the encouragement guys

After cutting the main bulk out of the long slot the next task was to cut the dovetails. Toolpost fitted to check the size. A lot of people go to some extremes to get the size of the dovetail correct, using gauges and pins for example. I find that just cutting, trial fitting and cutting some more until it fits works just fine.
QCTP Tool Holders Shaper Work The strip was then cut into sections on the bandsaw, deliberately making different sizes in pairs. Back onto the shaper for a clean-up.
QCTP Tool Holders Shaper Work Ouch ! That's a nasty "flame" cut

Not wishing to waste any material we'll let Dr Shaper have a look at it ....

QCTP Tool Holders Shaper Work There, that's better
QCTP Tool Holders Shaper Work I have slotted two holders for different sizes of HSS. The rest I shall do as and when depending on what I wish to fit.
I may try an angled slot to give positive back rake without grinding. Might as well give it a go.
Any other ideas anyone?