Does weight affect effectiveness of Follistim?

I am 5'8" and weigh 240 pounds. My RE has never mentioned my weight (to my surprise). I just finished my first round of Follistim (225 for 5 days and 300 for 6 days) Yesterday I had 3 follicles on the left (all around 10mm) and one on the right (around 13mm). The cycle ended up being cancelled because my estrogen just stayed around 100 (+ or - a bit) and did not change over the almost two week period. I started Provera last night to bring on my period and my RE is having me go to intramuscular injections for my next cycle because he says that with the subcutaneous injections the Follistim just isn't getting to where it needs to be and that the intramuscular will allow me to absorb more that way. My questions are regarding my weight and the intramuscular injections. I was on high doses of the Follistim, does my weight have anything to do with not absorbing the medication? Should I lose weight before trying again? Also, should I expect to see a difference doing the the intramuscular injections versus the subcutaneous? Is there some other medication that can be taken with Follistim to 'boost' the effects? If Follistim does not work are there any other alternatives or is that pretty much it? A lot of questions, I know, but I am really needing to know. Thanks!