The Meochrom 2 is a colour head, which can be used either for colour printing or to control the contrast when using variable contrast B&W papers, which is VERY useful.
The wooden plate is called the baseboard. Mine measures approx 40 x 55cm.
The 50mm 3-element lens will work for 35mm but not for 6x4.5 which requires a 75-90mm lens. In any case 3-element lenses aren't good, so you will want a better lens for 35mm too.
The Opemus 5 comes with different lens boards - the standard 39mm screw thread which will take a huge number of good lenses, and one with about a 23mm thread for which you nay struggle to find good lenses.
Although you can manage without an easel, life is much nicer with one. So perhaps add a second hand easel - even a cheap 2-blade 8x10 easel - to your shopping list. Also you will need negative holders for 35mm and 6x4.5 negs.
One nice feature of the Opemus 5 is that it has a split line focusser - a bit like on a rangefinder camera - which means you can get by without a grain focusser. Personally I prefer the grain focusser, but its certainly useable without one.
Not much maintenance. Regular light dusting and occasional oiling of moving parts is all mine gets.
I use a Philips type 13139 bulb in mine. I didn't have much difficulty ordering by mail order from the US a couple of yesrs ago but ordered some spares in case they become hard to find in future.
As far as printing slides goes the enlarger is capable but I don't know whether there are any positive colour papers and chemicals available these days.
I can't really comment on the price as I don't know your market.
Feel free to PM me if you have any more questions. I'm very happy with my Opemus 5.
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