[Paranoia (Mitch)]

Gday everyone. Didn't really want to start two posts so I figured I'd put my into & questions into one.

I live south of the river in perth (Baldivis). I've always been interested in space but never got into astronomy until a couple of months ago. Bought myself a pair of 9x63 binos & I'm hooked! Only had a handful of clear nights (that I've been free at least) since they arrived but I'm really enjoying myself.

Anyway, after many late nights researching telescopes I finally made a decision and ordered a Skywatcher BD 150mm mak-cass. Biggest reason I settled on this was it needed to be portable (most important as I intend to take it camping & my car is already a tetris struggle on trips).

I need some advice on eyepieces, my intent was to buy 2-3 quality plossls but I cannot work out which focal length to go for (I understand how to calculate magnification, but have no practical concept of it in an astronomy sense). I'm only interested in planets & the moon at this stage. Focal length of the mak is 1800mm & has option for both 1.25"/2" EPs.

Also filters, it seems pretty standard to go for a ND filter for the moon, are there good ones and bad ones? Are there any worth while planetary filters to start off with?
I've got about $300-$500 left in the telescope budget after buying the OTA and mount if that helps.

If you managed to get through that essay, thanks!
Cheers,
Mitch