baby shower suggestions- international planning

Thanks in advance for any constructive suggestions you might have.  I'm American living in England, my husband is British and I've lived here for 5 years.  I'm pregnant with my first and am trying to decide whether to have a baby shower or not.  They don't really do them much in the UK (although the trend is growing, it is certainly not the norm) and most of my closest family and friends are in the States.  We don't have any baby stuff, so a shower could be useful to get the little things and I think my best girlfriends and women in my family would have fun shopping.  Also my bridal shower was one of my favorite memories when looking back to when we got married, other than our wedding; mainly because I had it in the States and got to see close family and friends come together that I don't get to see often enough.  It was also fun and interesting to see all the amazing women from different eras/places in my life come together and get on so well.  One of my main concerns is the ability to travel whilst pregnant on a long haul transatlantic flight (8 hr) and if it would be worth the risk/cost.  So the questions are:

My mom and my aunt are offering to host a shower, is there one that is considered more appropriate? I'm quite close with both of them, my mom hosted my bridal shower. My aunts house is more suitable for more overnight guests, but I would have to travel less once in the US if it were at my mom's.

When- Because of the long flight involved/ safety, would it be okay to have it at 6 months?

How many guests? My bridal shower had about 20 guests, but I gather baby showers are smaller.  I found the bridal shower was really useful for close friends/ fam that couldn't make it over to England for the wedding and don't know if the same thought process should apply to a baby shower.

Should I invite my in laws? For the bridal shower I did and they actually came to the States for it.  I don't want them to feel at all obligated, but don't want to exclude them either.

 When should we send out the invites?  Most people will be traveling to attend if they come.

 Sorry for the length and thanks for your help:)