John

Unless the target object is quite bright (ie: magnitude 9 or brighter) I can't see it in any of my finders. I find fainter objects by "star hopping" using the finders and a good star map such as the Sky & Telescope Pocket Sky Atlas. The final finding of such targets is done at the eyepiece of the scope with a low power eyepiece. I really only use an RDF / illuminated reticule finder for getting the scope to the right part of the sky, to within a 4-6 degrees of my target. I've found this method works well for me

It is hard to beat the Baader Clicklock system.

If I was just going to use an illuminated reticule type finder on it's own it would be either a Telrad or a Rigel. I have also used the Baader Skysurfer III mentioned above and that worked well. The Baader Super Skysurfer V gets enthusiastic reviews: https://www.firstlightoptics.com/finders/baader-40mm-super-sky-surfer-v.html And if you really want to push the boat out, Tele Vue can help relieve you of quite a lot cash: https://www.widescreen-centre.co.uk/tele-vue-starbeam-finders.html Currently I have a Vixen RDF which I use from time to time but most of my refractor finding is done using 6x30 or 9x50 RACI optical finders.

So do many of the longer ones from these sources

Quite right and with the 150 having no collimation provision, if it is out (and they frequently are) it is harder to do anything about it.

A great deal of false colour I think. Personally I would much rather have one of the 152mm F/5.9's such as the one below for deep sky observing: http://ensoptical.co.uk/ts-optics-152mm-f5.9

I think your Baader zoom is the best tool for most of that complimented by a fixed focal length 2 inch. Any of the ones suggested would be good. I would also want decent quality UHC and O-III filters for the nebulae so another £200 needed there

I don't use the locking screws unless I am transporting the scope in the car. Once I got the primary collimated I found that the locking screws were actually putting it out again so I leave them loose in general use.

Having seen a few of the 350's and 400's I agree entirely with Ian. Try and see one up close and assess how practical it will be for you to store and setup the scope. The 400 is definitely a two person job. No doubt that you would notice the aperture difference at the eyepiece but if the scope is not practical initial enthusiasm can quickly wear off Whether the views are worth the cost and hassle is I think only a decision that you can come to. You might find that the BST's need to be upgraded to get the best from the larger, faster, aperture as well.

Actually I find using more magnification helps to tease out more detail on DSO's. For some targets you need the max true field just to fit the thing in but for smaller ones I'm usually using 75x - 150x or more.

It is hard I agree. At F/10 though, your scope does not pose much of a challenge optically to eyepieces so you don't need to spend big bucks to get good performance. My expectation would be that a 40 / 68 would perform pretty much the same as the 34 / 68 in your scope but the 40mm would show about 18% larger true field of view at a slightly lower magnification. Edit: There is a 35mm Aero ED 68 as well by the way.

Good to see and hear the initial report John Although plastics can be used successfully in scopes I'm kind of pleased to hear that they are minimal in this scope. The scope would not have looked out of place on the back page of a 1960's Sky & Telescope magazine, except it has been made today

I've found the Aero ED 40mm 68 degree pretty good in my scopes that range from F/9.2 to F/6.5. I use Ethos 21 and Nagler 31 in my F/5.3 12 inch dob. The Aero ED and clones are pretty light as well, for 2 inch wide fields. In your scope a 40mm 68 shows you a true field of 1.36 degrees and the 34mm 68 1.16 degrees. The Veil, in it's entirety needs around 3.5 degrees but you might squeeze the E or W segment into the 40mm / 68 true field, just !

The Meade 4000 plossls are the best for those adapters - they are slimmer than most plossl eyepieces.

You will have to excuse the non-scientists here for not knowing what the term doping means in this respect then All the definitions that I can find for the term refer to something quite different.