So i was thinking on making a hid fixture (like the ballast, lamp socket on a piece of wood) preferably i think i should buy a mh lamp, but what wattage should it be? I dont need that much light and weird bulky ballasts

I think i could buy a self ballasted one, but its more hard to find here on physical stores

I suggest you get a low wattage MH bulb with a warm CCT. One like this Philips bulb https://www.lightbulbs.com/product/philips-418798 It's not super bright but you would want to use it in larger room. Here is a ballast for it https://www.ebay.com/itm/226359066231 this bulb will last a long time but you NEED to be careful, MH bulbs have a tendency to explode towards the end of their lifespan, if the arc tube is not protected, which it isnt for this bulb, there is a pretty good chance the glass envelope shatters, which will send incredibly hot metal halides all over the place. I would highly suggest, for the reason of safety that you get some sort of clear glass enclosure to go over the bulb to prevent the risk of burns from a explosion, and I'd also recommend putting a metal piece on the side of wood where the bulb is located, to prevent a fire from starting if molten metal halide salts spray onto the wood from an explosion.

Also welcome to LG!

Nice!, but i prefer more of these screw in e27 MH bulbs, i think i should get a 70w mh one, but its ballast may be rare here that isnt these bulky metal outdoor ballasts

Do you live in the US or Europe? I guess I should have asked that initially.

Latin america. I once seen one of these mh lamps you described, but here its better a regular mh in terms of support and replacement without online stores

I've a tracklight for 70W double ended R7s MH lamps with a Philips electronic ballast, that I bought long time ago at Machsanei Teura lighting shop.
You can try to find one in the web. Lival and Baro, are good manufacturers of tracklights.

If you just want a bare HID bulb, I would recommend getting a coated MV lamp. Having a clear MH bulb (I would think) would hurt your eyes to look at. However, MV ballasts are also almost unobtainable. So, I would get a coated MV lamp with the appropriate wattage substitute MH ballast. Maybe a 100w MV lamp powered by a 70w MH ballast. MV lamps also don't explode as much as MH lamps. If you are interested in this, let me know and I can describe it in further detail. All readily accessible components. Hope this helps!
 

Wait, clear MV lamps emit UVC? I thought they only produced if their glass was made for that, ive seen clear MV greenish lights yet they didnt burn my eyes

Don't worry. Clear MV will not emit UVC unless the glass is designed to do that or the glass breaks.

Wait, clear MV lamps emit UVC? I thought they only produced if their glass was made for that, ive seen clear MV greenish lights yet they didnt burn my eyes

They don't emit UVC, it is just the arc tube is super-super bright and unpleasant to look at, even at just a glance. It wouldn't be a  great indoor light source unless it is diffused in some way, just so it creates less harsh shadows and is easier on the eyes.

If you just want a bare HID bulb, I would recommend getting a coated MV lamp. Having a clear MH bulb (I would think) would hurt your eyes to look at. However, MV ballasts are also almost unobtainable. So, I would get a coated MV lamp with the appropriate wattage substitute MH ballast. Maybe a 100w MV lamp powered by a 70w MH ballast. MV lamps also don't explode as much as MH lamps. If you are interested in this, let me know and I can describe it in further detail. All readily accessible components. Hope this helps!
 

MV ballasts are very easy to find outside the US, as they can also run some pulse-start MH lamps with an additional superimposed ignitor like Philips HPI-T, Osram HQI-BT 400W/D, etc...

So i was thinking on making a hid fixture (like the ballast, lamp socket on a piece of wood) preferably i think i should buy a mh lamp, but what wattage should it be? I dont need that much light and weird bulky ballasts

Small MH lamps in 35 and 70W are home friendly. Small electronic ballasts for them are too. Surplus shop track light can do useful purpose at home. For E26/E27 runned unattended better choose protected kinds. Uncoated protected lamps also show cool looking glasswork inside.

Mercury lamps in 50 and 80W are small and cute, though 125W ones are not too intimidating. Personally I like a soothing pinkish color of fresh coated deluxe mercury lamps, though some prefer uncoated ones for weird color and interestingly looking internals.

Small European specification 100V HPS lamps in 70W are cross-compatible to 70W MH electronic ballasts.

Some like to run small LPS lamps at home.

However from my experience larger HID lamps in 250W+ espectially exotic ones like colored metal halides are *much* more interesting visually to handle and run, because of larger burners and longer arcs! 

Coincidentally one of the local thrift shops here has just gotten a whole bunch of 70w chinese MH track lights for 5 euro a pop. Didn't buy any. The lamps themselves are chinese no name, date stamped 2009.

If i get any MH i'm going for 35w. 70w is just too bright for me - i have some Philips CDO already and it's B R I G H T for living room use.

@Laurens - For small MH floodlights, point them to the ceiling with no direct view. That way, you will get nice low-glare lighting, 70W and even 150W is OK. The best room light ever I had was with 150W Philips 830 color CMH on electronic ballast in a downlighter can pointing up.