Promoting from Bronze

Hi,

new player here (2 weeks, but I had some spare time and already got to level 25). I've read many posts here, but I'm still in the process of digesting all of it, so forgive me if I'm asking stupid questions I bought some heavy bots as soon as I had the necessary level, and of course got destroyed in whatever tier I got in. I also levelled up some bots which I maybe shouldn't have done, but what the heck. So I started to read here, treated myself to a christmas present (5th hangar and a Galahad), and am in the process of bringing my hangar up to 4/6, which will be finished soon. My five active robots are 

4/6 Gepard 2xMag 1xAphid (MM 325)
4/6 Gepard 1xMag 2xAphid (MM 325)
two 2/6 Boa  1xECC Thunder  1xR40M Orkan (MM 430)
2/5 Boa 1x ECC Thunder 1x E-SG Taran (MM390)

and I've been using a 3/5 Patton with 4x SURA-F Pinata (MM410) instead of the last Boa at times. I experimented with other robots, but found Boas most effective (apart from Gepards, which are just killers in Bronze).

I realize that I should upgrade my weapons on those Gepards next, as the MM score of the Boas is higher. But things are actually getting a bit boring there (70% success rate), and I'd like a peek at higher tiers. But I'd also like to avoid being promoted to a league that I can't handle, and I would prefer to keep a good Bronze lineup, whatever I do. So I wanted to get some additional robots and weapons, that would allow me to create a decent silver lineup (by using the weapons from my active robots of course).  In my storage I have (besides some low level robots) a lvl2 Galahad,  lvl6 Griffin, lvl6 Natasha, lvl6 Leo.  (No gold or WSP weapons except for a Trebuchet, plenty of AG weapons though, none of which are over level 5). Still plenty of silver available, this will probably change as I upgrade further.

So, what would be the best way to do this? I'm afraid to use 6/6 heavies, as this could drag me into gold tier (with high win percentage and wsp weapons). I've also read that WSP robots are only sensible in gold tier, so I'll spend my WSP points on weapons for now.

I'm definately confused about the galahad bonus, because some people write that it will increase my hangar score by 20% for all robots, while other people write that it is treated as heavy bot for MM purposes.  So my first question is: Which of those is true, and can I use something like a 2/8 Galahad in silver or should I shelve the Galahad until I'm ready for gold? 

The other question is less specific, more advice seeking. My original thought for silver was to find two medium robots that would replace the Gepards in the lineup, with the weapons from the Gepards. But those Gepards seem to be so strong, I wonder if this is at all sensible? Maybe it would be better to just use the 4/9 Gepards in silver too? So, essentially my other question is: Are there some easily accessible (AG) robots and weapons that I could buy so that I could create a decent silver lineup out of what I have? Or should I buy some gold or WSP weapons/robots to prepare for silve?

Best, F.