Thanks! I've just been playing with estlcam actually - it seems very good once you get over the lack of clarity in the interface and the way the settings are hidden away and highly contextual. The links to bits are doubtless helpful for US readers of this thread. I'd like to see some recommendations for bits available in Europe - most of the US shops the prices don't look so good once shipping and customs are taken into account.
Thanks, some day I’ll have this all figured out, but getting there, little by little. 3.3mm for the trochoidal and finish passes, so two passes on 1/4” 6061 Gary